added Base working GameState
added sound when jumping
added collision detection with gaps and walls
added score display
improved dispose() cleaning
added Back and Start buttons
removed starling stats box
Merge branch 'feature_game'
added wall creation to the initialization phase to avoid frame drop later on
removed useless variables
added rotation to the bird
added wall randomization
increased wall speed
reduced wallYGap
added wall texture randomization
Merge branch 'feature_game'
added BestScoreScreen
added ResultScreen
release apk should be with a captive runtime