Whitespace
Integrate MSE and color density better for low qualities

Separate condition for color density ratio makes quality configuration via error-threshold argument harder
Lower default quality range
Abort search if close enough
Merge remote-tracking branch 'pornel/lowerrange'
Merge remote-tracking branch 'pornel/closeenough'
Add dssim.c to Makefile
Add dssim.c to the other Makefile
Add dssim
Use range similar to MSE
Add interpolate.c to Makefiles
Polynomial interpolation