exit app when back button pressed
Merge branch 'ludum-dare' of github.com:minggo/cocos2d-x into ludum-dare
Merge pull request #35 from natural-law/ludum-dare

Add restart layer.
add powerby
Merge branch 'ludum-dare' of github.com:minggo/cocos2d-x into ludum-dare
make it movable on Android
Merge branch 'ludum-dare' of github.com:minggo/cocos2d-x into ludum-dare