code: function explode(sources) {
  		var json,
  			res = [];
  		sources.forEach(function(source) {
  			switch (path.extname(source)) {
  				case '.json':
  					json = grunt.file.readJSON(source);
  					res.push.apply(
  						res,
  						json.map(function(filepath) {
  							return path.dirname(source) + '/' + filepath;
  						})
  					);
  					break;
  				case '.js':
  					res.push(source);
  					break;
  			}
  		});
  		return res;
  	}
docs: If source is a JSON file, resolve the file
  as a new source list relative to that file.
  @param {Array<String>} sources
  @returns {Array<String>}