CONFIGURE: Add libmpeg2 as an optional dependency again
VIDEO: Add an MPEG 1/2 decoder
VIDEO: Update AVI code for parsing sword1/sword2 MPEG-2 files
VIDEO: Hook up MPEG decoder to AVI
VIDEO: Allow AVI frame rate to be overriden with a constant

Required for sword1/sword2 MPEG videos
SWORD1: Add back MPEG-2 video support
SWORD2: Add back MPEG-2 video support
VIDEO: Mark AVIDecoder as being used by sword1/sword2
CONFIGURE: Make the libmpeg2 properly require 0.4.0
Merge pull request #343 from clone2727/mpeg2-avi

Add back support for sword1/2 MPEG-2 cutscenes