Changes 6.7.75 -> 6.7.76:
* Windows: Fix import MOD when the username contains
  non-ascii characters.
* Windows: Fix displaying filename with non-ascii
  characters in the progress window when importing
  MOD files.
* Audio: Don't show error about not being able to
  open soundfont file when failed loading a sound
  file (we already show a general message about
  not being able to open the file).
  a file doesn't exist.
* Sequencer: Fix error messages popping up after
  pressing the Esc key when prompted to manually
  write new path in the file browser.
* Windows: Fix displaying paths with non-ascii
  characters in the file browser in the right-side
  sequencer tabs.
* Editor: Add options to set high priority for the
  OpenGL render thread and the OpenGL drawer thread.
* Preferences: Remove the OpenGL "Safe mode" option.
* Preferences: Move the "Vertical blank" OpenGL
  option into an "advanced" tab (since you normally
  don't want to touch this option).
* Preferences: Move the "OpenGL" tab to the right of
  the "GUI" tab.
* API: Add "message_is_base64" option to
  openProgressWindow