setup: Add default config for Xbox360 on Linux.

The Xbox360 controller is handled differently by different
operating systems, and the layout is different on Linux to Windows.
Detect the Linux layout and set some appropriate defaults.
Make vcproj release settings consistent

Max optimization settings for release that were derived from Eternity
are now effective for all 4 games. In addition, generate map files for
debugging purposes.
Merge branch 'master' of https://github.com/chocolate-doom/chocolate-doom
temporarily give all keys in PANIC cheat