consolidate all multivoc invalid file errors into MV_InvalidFile
renamed FX_PlayLooped to FX_Play and removed original FX_Play
removed device type parameter from FX_Init
moved several FX_ multivoc wrapper functions to the header and made them FORCE_INLINE
git-svn-id: https://svn.eduke32.com/eduke32@5814 1a8010ca-5511-0410-912e-c29ae57300e0