swap out svg for a bitmap image src if svg is unsupported

svg-fallback-swap.js

// if svg is unsupported (modernizr test)
// look for data-svg-fallback attr
// and switch out src on those images

(function (Modernizr, $, undefined) {
  if(!Modernizr.svg){
    var $elems = $('img[data-svg-fallback]');
    $elems.each(function(index){
      var img = $(this);
      img.attr('src', img.attr('data-svg-fallback'));
    });
  }
})(Modernizr, jQuery);