It's all 1 GUI and in C#

The option button now changes the volume.
Difficulty Buttons
Merge branch 'master' into sean

Conflicts:
	Assets/Scenes/Main_Menu.unity
	Assets/Scripts/GUISystem.cs
	Library/CurrentLayout.dwlt
	Library/ScriptAssemblies/Assembly-CSharp-firstpass.dll
	Library/ScriptAssemblies/Assembly-CSharp-firstpass.dll.mdb
	Library/ScriptAssemblies/Assembly-CSharp.dll
	Library/ScriptAssemblies/Assembly-CSharp.dll.mdb
	Library/ScriptAssemblies/Assembly-UnityScript-firstpass.dll
	Library/ScriptAssemblies/Assembly-UnityScript-firstpass.dll.mdb
	Library/ScriptAssemblies/Assembly-UnityScript.dll
	Library/ScriptAssemblies/Assembly-UnityScript.dll.mdb
	Library/assetDatabase3
	Library/guidmapper
	Library/metadata/6f/6f31d8cb1db8e408fb28e1594c58f665
	Library/metadata/e9/e9029ac82c055458c8fbc9ddd7476e8f
	Temp/UnityTempFile-00f138634d2844009a3bcf4cd010ee20
	Temp/UnityTempFile-26eb7a7e63e714e34b7242b81e394f0b
	Temp/UnityTempFile-55645ab3068fb4ad3b1dd0abeac87f97
	Temp/UnityTempFile-fd34e313a5d86400c891b86532567119
	Temp/__EditModeScene