Improve source file location structure

[GoogleCodeExporter]

All the files currently live in the source directory. It may be more 
manageable to break them up into logical sub-directories.

Post proposed structures here.

This may potentially tie in with issue #11 (as far as cutting down on bulk 
header includes).

Original issue reported on code.google.com by Jayschwa on 3 Jun 2010 at 4:16

[GoogleCodeExporter]

My initial thought is to clump files into directories based on which groups of 
files are inter-related and may be toggled by defines or platform.

Currently there are defines to toggle ctf, rogue, and xatrix. We may also want 
a toggle for single player stuff since I know many mod devs liked to strip that 
out. There are also two platforms (with a tiny bit of platform specific stuff) 
- unix and windows.

/source - always used stuff
/source/ctf
/source/singleplayer
/source/rogue
/source/rogue/singleplayer
/source/platform/unix - (linux, bsd, mac)
/source/platform/windows
/source/xatrix
/source/xatrix/singleplayer

Original comment by Jayschwa on 13 Jun 2010 at 10:59

[GoogleCodeExporter]

Agreed. However I maintain that header sorting should be on a much higher 
priority - we should be able to cut compile times down at least 60%.

Original comment by Jonno.5000 on 13 Jun 2010 at 11:03

[GoogleCodeExporter]

I went ahead and moved the cc_platform_x files to their respective 
/source/platform/unix and /windows directories in r456. It permits the CMake 
script to be much simpler since everything directly under /source can now be 
globbed.

Original comment by Jayschwa on 14 Jun 2010 at 3:01