Make kamikaze timer loops use level.num_entities instead of MAX_GENTITIES

Optimization. Many other loops use level.num_entities, there was no
special reason that MAX_GENTITIES was used for these.
Merge remote-tracking branch 'ioquake3/master'
Update and rename README to README.md

adding analytics, I'm ready for DevHC to get upset.
Improve github interperation of README.md
Add header for standalone game licensing
Rewrite commercial pk3 detection, include q3/ta demos, rtcw, et

Detect pk3s by checksum to be faster, but still confirm gamedir/filename to avoid false positives.
Check for commercial pk3s once at runtime instead of each time downloads are initiated.
Remove special handling for Q3 and Team Arena fs_game

Team Arena now require spearmint-patch-data in order to run.
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	README.md
Change githalytics for Spearmint
Remove unused variable 'sp' from FS_ComparePaks

Usage of the variable was removed in commit 240d065341d06e7518a351057b00f471f5129127.
Silence warnings about unused static functions in opengl2
Merge remote-tracking branch 'ioquake3/master'
Updating the tracking code properly.

Hopefully this new code will track properly.
Improve bot invisiblity logic

Don't consider players with harvester skulls or kamikaze to be invisible.
When bot is invisible, ignore far away players when going for the flag.
Moved checking if EntityIsShooting into EntityIsInvisible.
Short-circuit logic in EntityIsInvisible
Fix invisible logic to compile

Oops, broke compiling when reworking Tobias' patch a little.
Fix entityState_t weapon bits if WEAPONNUM_BITS > 8

Add comment to make it somewhat more clear why not just using WEAPONNUM_BITS.
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	README.md
Rewrite skin handling for dynamic remapping

Previously you would need a skin file for every way you wanted to remap a model.
Now you can setup/change skins using code. This allowing surfaces to toggle between
two shaders based on code or have multiple shaders for different damage levels
(without being limited to entire model or a ton of skin files).

Move skin file loading to cgame.
Merge player skins into one skin (will be useful for single model players later).

New system calls;

trap_R_RegisterShaderEx -- exposes ability to register shaders with 'lightmapIndex' other than LIGHTMAP_2D.
trap_R_AllocSkinSurface -- create reference for surface name/shader.
trap_R_AddSkinToFrame -- add skin (list of skin surfaces) for referencing in refEntity customSkin, must call each frame.
Fix compiling dedicated server