n-way collision checks and onBeginContact and onEndContact done and working. Also fixed issue in TweenManager.removeAll.

src/utils/Utils.js

@@ -265,3 +265,13 @@ if (typeof Function.prototype.bind != 'function') {
         };
     })();
 }
+
+/**
+* A polyfill for Array.isArray
+*/
+if (!Array.isArray) {
+  Array.isArray = function (arg) {
+    return Object.prototype.toString.call(arg) == '[object Array]';
+  };
+}
+