Changed signature of GLDEBUGPROCARB to match OpenGL GL_ARB_debug_output specs
Fix compile when system GLDEBUGPROCARB signature is without const

.. by just casting our DebugCallback to GLDEBUGPROCARB.
It shouldn't make a difference ABI-wise, if there is a const at
a parameter or not.

Fixes #61
Merge pull request #62 from DanielGibson/fix-gldebug-compile

Fix gldebug compile
Mirror source code directory structure in generated MSVC projects.
Removed unused FileSystem variables.
r_vidMode sanity check was off by 1.
Skip some common SWF tags (FileAttributes, Metadata and SetBackgroundColor) instead of failing to load a SWF file if any of them are encountered.
Prioritize source SWF and image (for SWF atlas) files over their binary equivalents in resources files when not in production mode. Now you can replace individual menus without having to extract and delete all the base/*.resources files first.
astyle
Added r_useVirtualScreenResolution cvar to control whether to do 2D rendering at 640x480 and stretch to the current resolution (default), or render at the current resolution.
Fixed warp effect not being centered when r_useVirtualScreenResolution was 0.
Reverted fs_resourceLoadPriority. Be aware to keep this changed if you work on mods or standalones. fixes #59 Player starts out with Soul Cube in Doom 3
Disabled tunnel vision. Fixes #33 Red screen flash on damage does not dissapear until load or full health
Fixed ERR_DROP resulting in a glitched screen with only the console accessible - show the main menu instead.
Fixed the autosave dialog being stuck on the screen when starting a map (map or devmap) via the command line, or before selecting Doom 3.
Astyle
Added doomclassic for Linux to CMake
Removed doomclassic networking functions
Define MAX_PATH for doomclassic when not compiled for Windows
Fixed some undefined types