ludus. Changes to ad control.

Rename on pause/resume to cleanup and initialize.
Ad control initialize is called when the activity is resumed or when the engine is created.
Changed initialize to handle multiple initialize calls - ignore initialize call if the ad control is already initialized.
Ad control cleanup is called when the activity is paused.
game_engine. Game view and engine changes.

Preserve the view EGL context if possible.
Rename the create native jni function to create.
Cleanup ad control when the native engine is destroyed.
Cleanup ad control in ad control destructor.
ludus. Fix an issue with ad control disable ad.

The disable ad method was not initialized correclty.
Also change initialization of java ad control global ref to happen at the end of initialize.