Basic functionality

1. Set up Project
2. Control Menu State
- Options Control
- Exit Game
- Credits (Read from txt-File)
- HowTo-Screen
- Basic First Person Controller
3. Options
- Save Settings in Options (XML)
- Write OptionsManager
- Store music- and soundlevel in Playerprebs
3. Audio
- Cube in Gameplay with 3D Sound
- Background sound in menu
- Control background music in menu with settings
- temp control audio in settings