audio/fasttracker2: Updates to v1.43

Changes since v1.41

v1.43 - 13.01.2021
- Sample tuning is now slightly more accurate when importing .IFF/.WAV/.AIFF
  samples. It can still be off by up to several cents, but this is because of a
  rather low sample pitch precision in FT2 (5-bit finetune + relative note).
- Bugfix: Fixed some scrollbar bugs in the instrument editor (when changing
  values, then changing instrument, and changing values again).
- New feature: Display middle-C (C-4) frequency in the instrument editor
- Some small optimizations and minor bugfixes

v1.42 - 01.01.2021
- Updated SDL from version 2.0.12 to version 2.0.14
- Windows: Because of a bugfix in SDL 2.0.14, the instrument selector keys
  (numpad) still work like they should regardless of the numlock state.
- Changed a flag when setting up the video renderer so that the program can
  properly run in rare cases where it wouldn't
- Some other minor fixes

(fox)