fix drag/overlap interaction

changes: when dragend resets draglist. 
this fixes overoutevents from a gameobject not firing after being drag.

Author: zehmaria

src/input/InputPlugin.js

@@ -764,6 +764,7 @@ var InputPlugin = new Class({
             }
 
             pointer.dragState = 0;
+            list.splice(0);
         }
 
         return 0;