tidy-ups in FS* stdio replacement functions. add new FS_filelength.
snd codec layer updates: changed codec_open() to operate only on a
stream pointer and moved all file open/close stuff to snd_codec.c.
codec_open now only returns true or false upon success or failure
instead of a stream pointer. added new snd_codec.c toplevel helper
S_CodecForwardStream(), which allows one codec to hand over its
stream from its codec_open() to another codec. Support for tracker
(mod) music, including support for Unreal umx containers. (might
be useful if we ever make a Nehahra version of the engine some day.
edit the makefiles to enable when compiling.)
git-svn-id: http://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@867 af15c1b1-3010-417e-b628-4374ebc0bcbd
