Log Message:
PC6001VX: update to 3.7.0.

Upstream changes:

3.7.0 2021/02/13
- Opening files by drag & drop is now available.
- Assigned double clicking window to toggle fullscreen.
- HAT switches on gamepad is now available. You can use digital gamepad or
  joystick for Nintendo Switch.
- Fixed inaccurate screen magnification ratio.
- Fixed freeze when initialized settings.
- Improved debug console font. Now you can see Hiragana and graphic
  characters in memory dump.