1) Added get_orig_retval for retrieving the original return value of an engine function
2) Fixed engfunc being called with EngFunc_CheckVisibility so that it now works as intended
3) Hooks should now also work with FM_WalkMove, FM_TraceToss, FM_TraceMonsterHull, FM_TraceHull,
FM_TraceModel, FM_TraceTexture, FM_TraceSphere, FM_GetBonePosition, FM_GetAttachment, FM_RunPlayerMove,
FM_StaticDecal, FM_BuildSoundMsg and FM_CheckVisibility
4) Reformatted comments in some header files so they look a bit neater
4101eea5e8