another gulp attempt

Gulpfile.js

var
  browserSync = require('browser-sync'),
  gulp        = require('gulp'),
  autoprefix  = require('gulp-autoprefixer'),
  concat      = require('gulp-concat'),
  filter      = require('gulp-filter'),
  jade        = require('gulp-jade'),
  sass        = require('gulp-ruby-sass'),
  sourcemaps  = require('gulp-sourcemaps'),
  traceur     = require('gulp-traceur'),
  uglify      = require('gulp-uglify'),
  reload      = browserSync.reload;

gulp.task('browser-sync', function () {
  browserSync({
    server: {
      baseDir: 'dist'
    }
  });
});

gulp.task('html', function () {
  gulp.src('src/jade/**/*.jade')
    .pipe(jade())
    .pipe(gulp.dest('dist'))
    .pipe(reload({stream: true}));
});

gulp.task('css', function () {
  var filter_css = filter('**/*.css');
  gulp.src('src/scss/**/*.scss')
    .pipe(gulp.dest('dist/assets/scss'))
    .pipe(sass({sourcemap: true, style: 'compressed', sourcemapPath: '/assets/scss'}))
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(filter_css)
    .pipe(autoprefix({browsers: ['last 2 versions', '> 1%', 'ie 8', 'ie 7']}))
    .pipe(sourcemaps.write('.', {sourceRoot:'/'}))
    .pipe(filter_css.restore())
    .pipe(gulp.dest('dist/assets/css'))
    .pipe(reload({stream: true}));
});

gulp.task('loader', function () {
  gulp.src([
      'bower_components/rsvp/rsvp.min.js',
      'bower_components/basket.js/dist/basket.js',
      'bower_components/requirejs/require.js',
      'src/loader/basket-loader.js',
      'src/loader/index.js'
    ])
    .pipe(concat('loader.js'))
    .pipe(uglify())
    .pipe(gulp.dest('dist/assets'))
    .pipe(reload({stream: true}));
});

gulp.task('vendors', function () {
  gulp.src('bower_components/zeptojs/src/zepto.js')
    .pipe(concat('zepto.min.js'))
    .pipe(uglify())
    .pipe(gulp.dest('dist/assets/vendors/zepto'));
});

gulp.task('js', function () {
  gulp.src([
      'src/js/**/*.js'
    ])
    .pipe(sourcemaps.init())
    .pipe(traceur())
    .pipe(concat('index.js'))
    .pipe(uglify())
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest('dist/app'))
    .pipe(reload({stream: true}));
});

gulp.task('default', ['html','loader','css','vendors','js']);

gulp.task('watch', ['browser-sync'], function () {
  gulp.watch("src/jade/**/*.jade", ['html']);
  gulp.watch("src/loader/**/*.js", ['loader']);
  gulp.watch("src/scss/**/*.scss", ['css']);
  gulp.watch("src/js/**/*.js", ['js']);
});