Update to GoogleAdMobAdsSdk-6.3.0

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Update to 3.0.25 of Google Play Services

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Fix compilation issue caused by new lint rules in SDK Tools 21.1

Yes, invalidateOptionsMenu() was added to Activity class in API
11, but MainActivity is a SherlockFragmentActivity, which implements
a compat version of the function.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>