Changes iOSDispatcher to use iframes to dispatch events

Instead of using window.location.href to trigger
the webView:shouldStartLoadWithRequest:navigationType:
in the UIWebView's delegate now it creates a new
iframe and set its source to the same URL
usend in window.location.href.

This is done because I was doing several calls to the native code and only the last one was reaching. Using iframes make it work