Added default UI button skins (need to change later), changed main Scrots file to a Screen, Added options and highscores screen, linked game screen to main screen
Merge branch 'master' of https://github.com/ayrten-cofounder/Ayrten-Scrots

Conflicts:
	core/src/com/ayrten/scrots/game/GameMode.java
	core/src/com/ayrten/scrots/screens/GameScreen.java