Hacky port for original Xbox

[JayFoxRox]

Currently crashes while loading sounds. Works but no sounds.

Most work is done in physfs (which is some horrible spaghetti code and rather messy in many ways) to remove unicode / UTF8 support.
Also obvious changes in main.c to set up Xbox platform.

A lot of the changes are also just debugPrints which are only temporary.

To download & install, use:

#
# ----- If you didn't have nxdk before; download nxdk first
#
git clone https://github.com/JayFoxRox/nxdk.git -b vvvvvv --recursive --depth=1
export NXDK_DIR=$(pwd)/nxdk
# 
# ----- Build and download the game now
#
git clone https://github.com/JayFoxRox/VVVVVV.git -b xbox --depth=1
cd VVVVVV/desktop_version
make -f Makefile.nxdk install_data 
make -f Makefile.nxdk 

If you already have nxdk, checkout these requirements:

• VVVVVV nxdk-sdl#2
• VVVVVV nxdk#69

Do not forget to run git submodule init && git submodule update

FIXME:

• Package license files
• Make changes compatible with dev platform
• Add debugger to observe memory usage
• Figure out if the backbuffer really has to be 32-bit
• Disable pointless menu options
• Fix audio
• Enable music streaming from HDD
• Fix button layout / help messages
• Avoid debugprint during boot
• Cleanup codebase
• QA
• vblank wait in main.cpp? (main timing is via SDL_GetTicks() and broken in XQEMU)
• Fix linear upscaler?
• Measure level size and figure out if re-encoding might be a good idea. 1.5MiB but we can probably tolerate this. Could be interesting for upstream though (advanced moddability)