20230423

• Fix songs using Xbox 360 XMA audio to not produce audio files twice as long as they should be when converting to Clone Hero format
• Fix CH song.ini to have diff_vocals_harm set to -1 if there are vocals but no harmonies
• Fixes to importing DTX files
  • Adjust tempos to match a DTXMania quirk in songs with many tempo changes
  • Better drum lane polyphony that more closely matches DTXMania behavior and spec (#142)
• First test of a work-in-progress MIDI spec for DTXMania-like drums, subject to change
  • New MIDI track is included with CH format export when present
  • Note names and color map are included in generated Reaper projects
  • "True Drums" imported from: Clone Hero (new track format as above), DTXMania, Rock Revolution (7-lane format), Guitar Hero III (drummer animations)