Added main menu

Main menu with "start", "tilt" and "exit" options added
Merge branch 'Fysiktest' of https://github.com/alexdbaldwin/Superbowl3D into Fysiktest

Conflicts:
	Library/EditorUserBuildSettings.asset
	Library/ScriptAssemblies/Assembly-CSharp.dll
	Library/ScriptAssemblies/Assembly-CSharp.dll.mdb
	Library/assetDatabase3
	Library/guidmapper
	Library/metadata/ac/acc38816984f85a49b5a94da279e88c6