Add a window menu
Created by: christopho
Add a window menu with at least the following entries:
- File
- Open Quest
- Quit
- Quest
- Start quest
- Stop quest
- Pause/Unpause
- Audio
- Mute
- Music volume
- Sound volume
- Video
- Fullscreen
- 2D acceleration
- Video filter
- Scale2x
- hq2x
- hq3x
- hq4x
- Zoom
- x1
- x2
- x3
- x4
When Solarus is launched without quest, this window would still open.