Similar to !6430 and !6362, this should make it possible to use native override for these classes.
-- v2: l3codecx.ax: Register the MP3 Decoder class. quartz: Register the MPEG Video Decoder class. quartz: Register the MPEG Audio Decoder class. quartz: Register the WAVE Parser class. quartz: Register the AVI Splitter class. quartz: Register the MPEG1 Splitter class. quartz: Move registration code to main.c. quartz: Simplify the filter registration code.