fasttracker2: update to b140

Changes since b139:

Beta #140 - 08.03.2019
- The 32-bit Windows version of the FT2 clone no longer requires the SSE2 CPU
  instruction set to function, but still takes advantage of it if it's present.
- Fixed a bug where the sample data scrollbar was broken on very long samples
- Fixed a bug where you could interact with the scopes while certain types
  of tool boxes were shown (Smp. Ed.).
- Fixed a bug where the "Add memory to sample" checkbox in the Echo tool
  (Smp. Ed.) was always unchecked the next time you opened the tool.
- Fixed a bug where "Get maximum scale" in the Volume tool (Smp. Ed.) could
  return bogus values on *very* silent parts.
- Fixed a bug where sample data could be incorrectly drawn when zoomed in as
  far as you get while scrolling, on a very big sample.
- Bug fix: Make sure a sample never exceeds max sample length while editing it
- Lowered max sample length from 2GB to 1GB to prevent crashes
- Some missing keyboard bindings were added to the "Keyboard" section in the
  help text.
- Some potential time-consuming tasks were put in threads to not temporarily
  halt the program (Smp. Ed. functions).
- The Echo tool in Smp. Ed. will now listen to mouse button down/ESC/SIGTERM
  as a way to force-quit it. This tool can take literally forever if abused.
- Code cleanup (now using "bool" type, etc)

(fox)