emulators/snes9x: Update to 1.60

Changes since 1.59.2:

- Fixed subscreen blending with master brightness < 100%.
- Fixed NMI timing when toggling enable bit. Fixes Chou Aniki--hack removed.
- Reverted an IPL map optimization that misses a weird edge case that caused
  The Great Battle III to lock up.
- Clamp MSU1 addition to max amplitude instead of wrapping. Proper MSU1 tracks
  will not be affected by this.
- Save mipmap_input parameter with customized GLSL and slang shaders.
- Actually use mipmap_input parameter.
- Optimized subscreen math with help from Dwedit.
- Revert to measured APU clock speed instead of nominal speed. Fixes An
  American Tail.
- Fixed broken BPS patch support. (ArtiiP)
- Fixed MSU1 track restarting on load state.

libretro:
- Added ability to use Satellaview data in same directory as ROM.
- Fixed deviation from proper libretro spec.
- Added option to use the software NTSC filter. (stellarporter)

GTK:
- Added icons to the entries to clear binding assignments.
- Fixed overlap in xBRZ multithreading.
- Changed glFenceSync option to an OML_sync option that works better.
- Fixed accumulation of partial pixel data on mouse motion when we update the
  mouse position more than once per frame.
- Allow one key to be bound to many controller buttons on the same controller.
- Force menu and button icons.
- Add the view menu to right-click when SNES mouse isn't used.
- Remove unused status bar option.
- Startup background can be changed in snes9x.conf.
- Improved PortAudio driver.

Unix:
- Fixed sound output that broke with APU refactor.

(nia)