Main menu and control of sound and music.
Merge branch 'master' of https://github.com/machpavel/autickax

Conflicts:
	Auticka/src/cz/mff/cuni/autickax/Autickax.java
	Auticka/src/cz/mff/cuni/autickax/gamelogic/SubLevel1.java
	Auticka/src/cz/mff/cuni/autickax/gamelogic/SubLevel2.java
	Auticka/src/cz/mff/cuni/autickax/scene/GameScreen.java
	Auticka/src/cz/mff/cuni/autickax/scene/MainMenuScreen.java