game_engine. Add generic java error handling to the game interface.

Remove the old error handling mechanism.
On any error on the engine or game lib side, pass error data throuh an extras bundle in an intent passed back to the calling activity.
For activites derived from the engine Game activity, it is still possible to override the implementation of the engine event handle onError method to create custom errro event handling.
Renamed error constants.
Modified test game to display more meaningful error data - using the data returned in the error bundle.
This is the first step for better error handling, the next step will throw exception from the native layer, that will be caught in the engine java layer.