Make R_LerpTag return qfalse if MDR tag does not exist

Elite Force SDK has trap_R_LerpTag return void, so this shouldn't cause issues for iostvef.
Allows new games to check if a tag exists in a MDR model.
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	code/renderergl1/tr_model.c
spearmint: Fix possible uninitialized variables in GL1 R_LerpTag
Switched runtime library to Multithreaded DLL to fix build on VS2012.
Merge pull request #69 from RobertoEstrada/master

Switched runtime library to Multithreaded DLL to fix build on VS2012.
Skip merging ioquake3/master MSVC commit
spearmint: Expose control of more bot trace contentmasks to Game VM

Also expose pass entity num for AAS_DropToFloor.

To maintain the same behavior in game VM;
  - AAS_DropToFloor: Use passent 0, contentmask CONTENTS_SOLID
  - Others: Use contentmask CONTENTS_SOLID|CONTENTS_PLAYERCLIP
spearmint: Fix reconnecting bot at map change

Before it use to run ClientBegin for playernum based on bot clientnum.
It was wrong when there were splitscreen players added before bot was added.
spearmint: Fix uninitialized variable warnings from older MinGW/GCC
spearmint: Change opengl2-readme.txt for Spearmint

Remove installing. Change running for Spearmint.
spearmint: Make r_dlightMode 3 work

Dlight culling must be called too many times, and loses some dlights,
when r_dlightMode 3 is set. Might cause issues in other cases too, so just
disable it for now. It's from ET and might not be that much benefit anyway.
Merge remote-tracking branch 'upstream/master'