Correct Accela Mk3 default coefficients
Don't expose filter internal state. Sprinkle some const
Merge branch 'master' of github.com:opentrack/opentrack

Conflicts:
	facetracknoir/tracker.cpp
	ftnoir_filter_accela/ftnoir_filter_accela.cpp
	ftnoir_filter_accela/ftnoir_filter_accela.h
	ftnoir_filter_base/ftnoir_filter_base.h
	ftnoir_filter_ewma2/ftnoir_filter_ewma2.cpp
	ftnoir_filter_ewma2/ftnoir_filter_ewma2.h
Fix MSVC build. Also, minor reformat