Fixes Client Push for Android

I figured out why client push was broken using the native client. Turns out that you have to enable it in parse before using it. So, after doing that, client-side push seemed to work without hacks. I cleaned up the PushUtils as a result, so you'll notice a cleaner API. I also fixed some transitions, and refitted the DialogBlocker for good measure.
Merge pull request #150 from steffanc/push-fixes

Fixes Client Push for Android