Changed the approach used to destroy the WebView instance for #15 & fixing #32

Reimplementing #15:
Changed WebView.destroy to loading an empty page due to bugs mentioned here: http://stackoverflow.com/questions/6201615/how-do-i-stop-flash-after-leaving-a-webview?rq=1

Repositioned super.onDestroy to the end of onDestroy


Also fixing issue #32