ProTracker 2 clone v1.20

• Song BPM is now more accurate (it used to be slightly off for some BPMs).
  Please note that every Amiga's system clock is off by a very small fraction.
  This means that the true PT BPM (based on CIA) differs very slightly from
  machine to machine, so the PT2 clone's BPM will not precisely match a real
  Amiga.
• Added a delay when using left/right/delete/backspace keys in text edit mode.
  This makes it harder to do accidents!
• Bugfix: MOD2WAV didn't stop rendering even if a F00 pattern command was
  triggered.
• Bugfix: PAT2SMP would sometimes not render the very last song tick