Log Message:
fasttracker2: update to b149

Changes since b148:

Beta #149 - 18.04.2019 (updated the same day)
- Bug fix: If the window is minimized while you double-click on an associated
  module in your OS, maximize the window before asking if you want to discard
  unsaved changes.
>> Updates:
- Updated rtmidi to version 4.0
- Windows: Updated SDL to version 2.0.9 (finally found a way to prevent a
  serious bug with 2.0.9, hence why I have been using 2.0.8 for a long time).
- Increased "volume toolbox" (Smp. Ed.) range from -200..200% to -500..500%
- Windows: Default Disk Op. directory is now "\Users\username"