Merge CGame and UI VMs (issue 41)

Merge ui VM into cgame VM.
Fix ui_load command.
Remove lerpFrame_t from ui_local.h files, include cg_local.h instead.
Remove UI_DrawProportionalString from cg_drawtools.c, use UI code directly. Team Arena connect screen uses new font now.
Merge BG_RegisterClientCvars with CG_RegisterCvars

CG_RegisterCvars gets called before UI_Init now that cgame and ui VMs are merged, so BG_RegisterClientCvars isn't needed anymore.
Move client model command to cgame

Now usable for all local players. 2model, 3model, 4model.
Cannot be used in menu anymore though as cg_consolecmds.c commands aren't registered yet.

Also, allow vm commands to override vm cvars in Cmd_ExecuteString.
Revert making cg_thirdPerson cheat protected

Accidentally added CVAR_CHEAT to cg_thirdPerson in commit that merged BG_RegisterClientCvars with CG_RegisterCvars.
Update READM for vm_ui removal
Replace tabs in README with spaces
Remove FS_UI_REF and some UI VM references in comments
Remove FS_CGAME_REF and FS_ClearPakReferences

FS_CGAME_REF was used by pure system code that I removed. It was used for sending checksum of pk3 that cgame.qvm is in to server.
Made referenced a qboolean, not storing flags anymore.
All of the FS_ClearPakReferences usages don't make sense.
- FS_Restart called it after freeing all the pk3s, so didn't do anything.
- sv_init.c called it before FS_Restart, which free all the pk3s and then tries to clear referenced flags.
- CL_Vid_Restart_f called it to clear cgame flag, which Spearmint doesn't care about.
Merge remote-tracking branch 'spearmint/master'

Conflicts:
	Makefile
	code/cgame/cg_consolecmds.c
	code/cgame/cg_drawtools.c
	code/cgame/cg_main.c
	code/client/cl_main.c
	code/game/bg_misc.c
	code/q3_ui/ui_local.h
	code/ui/ui_local.h