Merge pull request #522 from BSzili/master

Added a safety check to GL_ResetBinds for multitexture extensions.
[SP] Merge fix to JASP so that NPCs can pick up bowcaster/repeater.
[JK2SP] Minor cleanup in g_itemLoad.cpp
[MP] Adds sv_blockJumpSelect cvar defaulting to 1.
Potentially blocking the use of modded client to set FP_LEVIATHAN to ucmd::forcesl and using +useforce.
Might interfere with their normal selection but they are trying to cheat so..
[MP] Fix missing cvar object.