audio/fasttracker2: Updates to v1.36

Changes since v1.35

v1.36 - 05.10.2020
- Bugfix: The 'S' volume column effect (set vibrato speed) should be ignored if
  the parameter is zero.
- Bugfix: The Kxx (key off) effect was not behaving like FT2 for values >$0f
- Bugfix: If attempting to WAV-render a song with an EEx (pattern delay) effect
  on the first row of a pattern, the render would end too early.
- Bugfix: In Disk Op., when loading a new module/sample, change the loaded
  filename extension according to save mode (f.ex. "test.xm" -> "test.wav").
- When changing the song position from the UI, reset global volume, and also
  reset pattern delay and other possible conflicts. FT2 doesn't do this, but I
  feel that this is a sensible thing to do.
- Made the About screen a bit more visually appealing
- Updated the "Known bugs" section of the help text
- Replayer code cleanup

(fox)