Fixed up IGameHelpers.h such that it no longer requires HL2SDK headers if a function doesn't need them --HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%402144
--HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%402095