implemented login screen,
no start action as so far
added loginscreen, highscore
and save userdata(playername, score)
added LevelScreen
Merge branch 'menu_login'

Conflicts:
	core/src/com/aau/auris/game/AURIS_Game.java
	desktop/src/com/aau/auris/game/desktop/DesktopLauncher.java
updated, resolved conflicts