Log Message:
audio/fasttracker2: Updates to v1.30

Changes since v1.27

v1.30 - 23.08.2020
- Fixed an off-by-one issue when dithering is enabled in 16-bit audio mode
- The WAV renderer now defaults to the same frequency/bitdepth as the ones
  selected in the "I/O devices" config screen.

v1.29 - 18.08.2020
- Fix wraparound-issues when using Tab in the pattern editor

v1.28 - 16.08.2020
- Bugfix: Don't redraw the instrument switcher when pressing numpad keys
  while certain screens (about/config/help/nibbles) are open.
- Slightly increased the volume precision in the audio channel mixer.
  This is most likely not measurable.
- Fixed some errors in the help text
- Small code cleanup