Log Message:
fasttracker2: update to b137

Changes since b135:

Beta #137 - 14.02.2019
- Mouse scaling was 100% broken on Macs with retina displays (high-DPI).
  Sorry! This is fixed now.

Beta #136 - 14.02.2019
- French keyboard layout users can now enter numbers in the pattern data
  with the left SHIFT key (like normal for the FR layout).
- You can now toggle extended pattern editor mode with the print screen key
  (like in real FT2. You can also use CTRL+Z as always).