iOS support

Starting off of @hyliker and @xydudu's changes I've added strong iOS support that can be installed with

    cordova plugin add https://github.com/benjie/phonegap-parse-plugin

The revision history is a bit messy as I flailed around not really knowing what I was doing; but I think the resultant changes are pretty solid.

I'm not sure how this affects the Android side of things; you may need to re-test it under Android.