Added a "Nearest Filtering" option for testing.
Renamed Nearest and Linear Filtering to Force Nearest/Linear Filtering.
Made sure that both options aren't active at the same time.
Merge remote-tracking branch 'upstream/master' into nearest_filtering
update submodules
Merge branch 'nearest_filtering' of https://github.com/AdmiralCurtiss/ppsspp into AdmiralCurtiss-nearest_filtering

Conflicts:
	ffmpeg
	lang