gruntfile with some modifications to run PHP and enable livereload with the grunt-contrib-watch component and lots of cruft. Originally based off the gruntfile included with generator-webapp.

Gruntfile.js

// Generated on 2013-10-16 using generator-webapp 0.4.3
'use strict';

// # Globbing
// for performance reasons we're only matching one level down:
// 'test/spec/{,*/}*.js'
// use this if you want to recursively match all subfolders:
// 'test/spec/**/*.js'

module.exports = function (grunt) {
    // show elapsed time at the end
    require('time-grunt')(grunt);
    // load all grunt tasks
    require('load-grunt-tasks')(grunt);
    grunt.loadNpmTasks('grunt-php');
	
    grunt.initConfig({
        // configurable paths
        yeoman: {
            app: 'app',
            dist: 'dist'
        },
        watch: {
        	copyPhp: {
        		files: [
				'<%= yeoman.app %>/*.php',
				'<%= yeoman.app %>/styles/{,*/}*.{scss,sass}'
				],
			tasks: ['compass:server','copy:php'],
			options: {
				livereload: true,
			},
		},
//            compass: {
//                files: ['<%= yeoman.app %>/styles/{,*/}*.{scss,sass}'],
//                tasks: ['compass:server', 'autoprefixer']
//            },
            styles: {
                files: ['<%= yeoman.app %>/styles/{,*/}*.css'],
                tasks: ['copy:styles', 'autoprefixer']
            },
            livereload: {
                options: {
                    livereload: '<%= connect.options.livereload %>'
                },
                files: [
                    '<%= yeoman.app %>/*.html',
					'<%= yeoman.app %>/*.php',
                    '.tmp/styles/{,*/}*.css',
                    '{.tmp,<%= yeoman.app %>}/scripts/{,*/}*.js',
                    '<%= yeoman.app %>/images/{,*/}*.{png,jpg,jpeg,gif,webp,svg}'
                ]
            }
        },
        connect: {
            options: {
                port: 9000,
                livereload: 35729,
                // change this to '0.0.0.0' to access the server from outside
                hostname: 'localhost'
            },
            livereload: {
                options: {
                    open: true,
                    base: [
                        '.tmp',
                        '<%= yeoman.app %>'
                    ]
                }
            },
            test: {
                options: {
                    base: [
                        '.tmp',
                        'test',
                        '<%= yeoman.app %>'
                    ]
                }
            },
            dist: {
                options: {
                    open: true,
                    base: '<%= yeoman.dist %>'
                }
            }
        },
        clean: {
            dist: {
                files: [{
                    dot: true,
                    src: [
                        '.tmp',
                        '<%= yeoman.dist %>/*',
                        '!<%= yeoman.dist %>/.git*'
                    ]
                }]
            },
            server: '.tmp'
        },
        jshint: {
            options: {
                jshintrc: '.jshintrc'
            },
            all: [
                'Gruntfile.js',
                '<%= yeoman.app %>/scripts/{,*/}*.js',
                '!<%= yeoman.app %>/scripts/vendor/*',
                'test/spec/{,*/}*.js'
            ]
        },
        mocha: {
            all: {
                options: {
                    run: true,
                    urls: ['http://<%= connect.test.options.hostname %>:<%= connect.test.options.port %>/index.html']
                }
            }
        },
        compass: {
            options: {
                sassDir: '<%= yeoman.app %>/styles',
                cssDir: '.tmp/styles',
                generatedImagesDir: '.tmp/images/generated',
                imagesDir: '<%= yeoman.app %>/images',
                javascriptsDir: '<%= yeoman.app %>/scripts',
                fontsDir: '<%= yeoman.app %>/styles/fonts',
                importPath: '<%= yeoman.app %>/bower_components',
                httpImagesPath: '/images',
                httpGeneratedImagesPath: '/images/generated',
                httpFontsPath: '/styles/fonts',
                relativeAssets: false,
                assetCacheBuster: false
            },
            dist: {
                options: {
                    generatedImagesDir: '<%= yeoman.dist %>/images/generated'
                }
            },
            server: {
                options: {
                    debugInfo: true
                }
            }
        },
        autoprefixer: {
            options: {
                browsers: ['last 1 version']
            },
            dist: {
                files: [{
                    expand: true,
                    cwd: '.tmp/styles/',
                    src: '{,*/}*.css',
                    dest: '.tmp/styles/'
                }]
            }
        },
        // not used since Uglify task does concat,
        // but still available if needed
        /*concat: {
            dist: {}
        },*/
        requirejs: {
            dist: {
                // Options: https://github.com/jrburke/r.js/blob/master/build/example.build.js
                options: {
                    // `name` and `out` is set by grunt-usemin
                    baseUrl: '<%= yeoman.app %>/scripts',
                    optimize: 'none',
                    // TODO: Figure out how to make sourcemaps work with grunt-usemin
                    // https://github.com/yeoman/grunt-usemin/issues/30
                    //generateSourceMaps: true,
                    // required to support SourceMaps
                    // http://requirejs.org/docs/errors.html#sourcemapcomments
                    preserveLicenseComments: false,
                    useStrict: true,
                    wrap: true
                    //uglify2: {} // https://github.com/mishoo/UglifyJS2
                }
            }
        },
        rev: {
            dist: {
                files: {
                    src: [
                        '<%= yeoman.dist %>/scripts/{,*/}*.js',
                        '<%= yeoman.dist %>/styles/{,*/}*.css',
                        '<%= yeoman.dist %>/images/{,*/}*.{png,jpg,jpeg,gif,webp}',
                        '<%= yeoman.dist %>/styles/fonts/{,*/}*.*'
                    ]
                }
            }
        },
        useminPrepare: {
            options: {
                dest: '<%= yeoman.dist %>'
            },
            html: '<%= yeoman.app %>/index.html'
        },
        usemin: {
            options: {
                dirs: ['<%= yeoman.dist %>']
            },
            html: ['<%= yeoman.dist %>/{,*/}*.html'],
            css: ['<%= yeoman.dist %>/styles/{,*/}*.css']
        },
        imagemin: {
            dist: {
                files: [{
                    expand: true,
                    cwd: '<%= yeoman.app %>/images',
                    src: '{,*/}*.{png,jpg,jpeg}',
                    dest: '<%= yeoman.dist %>/images'
                }]
            }
        },
        svgmin: {
            dist: {
                files: [{
                    expand: true,
                    cwd: '<%= yeoman.app %>/images',
                    src: '{,*/}*.svg',
                    dest: '<%= yeoman.dist %>/images'
                }]
            }
        },
        cssmin: {
            // This task is pre-configured if you do not wish to use Usemin
            // blocks for your CSS. By default, the Usemin block from your
            // `index.html` will take care of minification, e.g.
            //
            //     <!-- build:css({.tmp,app}) styles/main.css -->
            //
            // dist: {
            //     files: {
            //         '<%= yeoman.dist %>/styles/main.css': [
            //             '.tmp/styles/{,*/}*.css',
            //             '<%= yeoman.app %>/styles/{,*/}*.css'
            //         ]
            //     }
            // }
        },
        htmlmin: {
            dist: {
                options: {
                    /*removeCommentsFromCDATA: true,
                    // https://github.com/yeoman/grunt-usemin/issues/44
                    //collapseWhitespace: true,
                    collapseBooleanAttributes: true,
                    removeAttributeQuotes: true,
                    removeRedundantAttributes: true,
                    useShortDoctype: true,
                    removeEmptyAttributes: true,
                    removeOptionalTags: true*/
                },
                files: [{
                    expand: true,
                    cwd: '<%= yeoman.app %>',
                    src: '*.html',
                    dest: '<%= yeoman.dist %>'
                }]
            }
        },
        // Put files not handled in other tasks here
        copy: {
            dist: {
                files: [{
                    expand: true,
                    dot: true,
                    cwd: '<%= yeoman.app %>',
                    dest: '<%= yeoman.dist %>',
                    src: [
                        '*.{ico,png,txt}',
						'*.{php,phpc}',
                        '.htaccess',
                        'images/{,*/}*.{webp,gif}',
                        'styles/fonts/{,*/}*.*',
                        'bower_components/sass-bootstrap/fonts/*.*'
                    ]
                }]
            },
			php: {
				files: [{
					expand: true,
					dot: true,
					cwd: '<%= yeoman.app %>',
					dest: '<%= yeoman.dist %>',
					src: [
						'*.{php,phpc}'
					]
				},
				{
					expand: true,
					dot: true,
					dest: '<%= yeoman.app %>/styles',
					cwd: '.tmp/styles/',
					src: '{,*/}*.css'
				}]
			},
            styles: {
                expand: true,
                dot: true,
                cwd: '<%= yeoman.app %>/styles',
                dest: '.tmp/styles/',
                src: '{,*/}*.css'
            }
        },
        modernizr: {
            devFile: '<%= yeoman.app %>/bower_components/modernizr/modernizr.js',
            outputFile: '<%= yeoman.dist %>/bower_components/modernizr/modernizr.js',
            files: [
                '<%= yeoman.dist %>/scripts/{,*/}*.js',
                '<%= yeoman.dist %>/styles/{,*/}*.css',
                '!<%= yeoman.dist %>/scripts/vendor/*'
            ],
            uglify: true
        },
        concurrent: {
            server: [
                'compass',
                'copy:styles'
            ],
            test: [
                'copy:styles'
            ],
            dist: [
                'compass',
                'copy:styles',
                'imagemin',
                'svgmin',
                'htmlmin'
            ],
			php: [
				'php:watch',
				'watch'
				]
        },
        bower: {
            options: {
                exclude: ['modernizr']
            },
            all: {
                rjsConfig: '<%= yeoman.app %>/scripts/main.js'
            }
        },
		php: {
			watch: {},
			options: {
				base: 'app',
				keepalive: true
			}
		}
    });

    grunt.registerTask('server', function (target) {
        if (target === 'dist') {
            return grunt.task.run(['build', 'connect:dist:keepalive']);
        }

        grunt.task.run([
            'clean:server',
            'concurrent:server',
            'autoprefixer',
            'connect:livereload',
            'watch'
        ]);
    });

    grunt.registerTask('test', [
        'clean:server',
        'concurrent:test',
        'autoprefixer',
        'connect:test',
        'mocha'
    ]);

    grunt.registerTask('build', [
        'clean:dist',
        'useminPrepare',
        'concurrent:dist',
        'autoprefixer',
        'requirejs',
        'concat',
        'cssmin',
        'uglify',
        'modernizr',
        'copy:dist',
        'rev',
        'usemin'
    ]);

    grunt.registerTask('default', [
        'jshint',
        'test',
        'build'
    ]);
	
    grunt.registerTask('phpwatch', [
		'clean:server',
		'compass',
		'copy:styles',
		'copy:php',
		'autoprefixer',
		'concurrent:php',
    ]);
};