fix(*): Closes #235 - pass right context in case of ctrlAs syntax

Author: codef0rmerz

src/angular-dragdrop.js

@@ -47,7 +47,7 @@ var jqyoui = angular.module('ngDragDrop', []).service('ngDragDropService', ['$ti
       // call either $scoped method i.e. $scope.dropCallback or constructor's method i.e. this.dropCallback.
       // Removing scope.$apply call that was performance intensive (especially onDrag) and does not require it
       // always. So call it within the callback if needed.
-      return (scope[callback] || scope[constructor][callback]).apply(scope, args);
+      return (scope[callback] || scope[constructor][callback]).apply(scope[callback] ? scope : scope[constructor], args);
 
       function extract(callbackName) {
         var atStartBracket = callbackName.indexOf('(') !== -1 ? callbackName.indexOf('(') : callbackName.length,