[SP] Remove R_LoadDataImage
[JK2SP] Fixed yes/no menu items.
[MP] Fix potential buffer overflow in PS_ReadPrimitive

Found by Coverity.
[MP] Fix unchecked buffer size issues in l_script.cpp and l_precomp.cpp

Found by Coverity.
[MP] Fix potential buffer overflow caused by long tcMod surfaceSprites, and ss args

Found by Coverity.
[SP] Fix potential buffer overflow caused by long tcMod surfaceSprites, and ss args

Found by Coverity.
Fix OOB access in CM_EdgePlaneNum
[JK2SP] Instant save/load no longer shows up as ??? in the menu.
Merge pull request #547 from BSzili/master

JK2SP menu fixes
[SP] Some fixes for issues in both SP games pointed out by Coverity.
[SP] Fix OOB access in CM_EdgePlaneNum
[SP] Fix UI_FeederItemText and SE_GetString with JK2 Mode having redundant code.
[JK2SP] Disable cStringPackage::Load(char *) because its not used
Switch strncmp to Q_stricmpn in qcommon/strip.cpp
[SP] Some minor fixes for both SP games.

Also a copy-paste error was fixed in cg_players.cpp of JK2.  Reported by Coverity.
[MP] Fix spawn field / vehicle field offset not being size_t storage type.
[SP] Fix spawn field / vehicle field offset not being size_t storage type.
[SP] Some buffer, cast, and operator fixes for SP games.
[MP] Some buffer, types, and cast fixes.
[JK2SP] Fix an invalid vector copy of player maxs into mins in NAVNEW_TestNodeConnectionBlocked.
[MP] Fix detail shader code for dedicated for comformity.