Added and completed "delay" for Underbar.

Author: austentalbot

src/underbar.js

@@ -333,6 +333,10 @@ var _ = {};
   // parameter. For example _.delay(someFunction, 500, 'a', 'b') will
   // call someFunction('a', 'b') after 500ms
   _.delay = function(func, wait) {
+    var args=Array.prototype.slice.call(arguments, 2);
+    setTimeout(function() {
+      func.apply(this, args);
+    }, wait);
   };