code: function cleanContent() {
      function transform(file, cb) {
          file.contents = new Buffer((function (src) {
              var lines = src.replace('_.mixin({\n','').split('\n'),
                  last = lines.pop();
              // handle empty lines at the end of the file
              while(last===''){
                  last = lines.pop();
              }
              return lines.join('\n');
          })(String(file.contents)));
          cb(null, file);
      }
  
      return require('event-stream').map(transform);
  }
docs: This method is used as a modifier for minification to clean up
  the stream a bit.