Misc bug fixes.

* Fixed issue where if a null NotificationOpenedHandler was passed into the constructor a null error would be thrown when a notification is opened.
   - Added overloaded construct to support not passing in this parameter at all if you don't want a callback.
* Fixed issue were a notification would not be shown if your AndroidManifest.xml didn't include a icon or was hard coded to a file instead of using @drawable/ic_launcher.
* Fixed sendPurchase to not throw a null error if the player did not register with GameThrive.
Updated jar to match the last code commit.
Merge branch 'master' of https://github.com/GameThrive/GameThrive-Android-SDK