Updated Android/Diagnostic for Cordova 2+ Compatibility

Needed the Diagnostic Plugin, currently using 2.3, therefore i had to make those quick fixes.

They make is work, javascript was simply changed as per [this stackoverflow article](http://stackoverflow.com/questions/11613274/window-plugins-undefined-in-cordova-2-0-0#11621631).

I understand that sometime in the near future it would also be required that Diagnostic.java would need to be changed to extend `CordovaPlugin` directly - but at least this fix makes the plugin catch up with the 2.0 series.