Linux (gtk):
- Remove gtk pixbuf usage on drawing DS screens, use only Cairo.
- Use transformation matrix to handle touchscreen coordinates.
- Adapt RGB555-to-RGBA8888 conversion code from Cocoa port, should result in brighter colour.
- Re-enable fullscreen menu item on start.


git-svn-id: https://svn.code.sf.net/p/desmume/code/trunk@5002 5577840e-afb3-4e59-9ef3-2b7f898b1952
Linux (gtk):
- Fix possible stack overflow if video filter resolution is high enough.
- Fix not being able to toggle HUD when paused.
- Fix HUD 3d fps display when there is frameskip.


git-svn-id: https://svn.code.sf.net/p/desmume/code/trunk@5003 5577840e-afb3-4e59-9ef3-2b7f898b1952