Code consistency fixes

Author: mdeboer

dist/wow.js

@@ -47,10 +47,10 @@
     Util.prototype.emitEvent = function(elem, event) {
       if (elem.dispatchEvent != null) {
         return elem.dispatchEvent(event);
-      } else if (elem[event] != null) {
+      } else if (event in (elem != null)) {
         return elem[event]();
-      } else if (elem['on' + event] != null) {
-        return elem['on' + event]();
+      } else if (("on" + event) in (elem != null)) {
+        return elem["on" + event]();
       }
     };
 

dist/wow.min.js

@@ -30,10 +30,10 @@ class Util
   emitEvent: (elem, event) ->
     if elem.dispatchEvent? # W3C DOM
       elem.dispatchEvent(event)
-    else if elem[event]? 
+    else if event of elem? 
       elem[event]();
-    else if elem['on'+event]?
-      elem['on'+event]();
+    else if "on#{event}" of elem?
+      elem["on#{event}"]();
 
   addEvent: (elem, event, fn) ->
     if elem.addEventListener? # W3C DOM