Add Transfer-View packground to file save and load.
Threshold value for NPR Ray Caster.
Separate power for border value for NPR Ray Caster from phong shading power.
Stop, start and restart buttons (How should stop be handled? Reset? Continue?).
Save and Load TL ray caster setting.
Export images.
Calculate interval length to harmonize _drawImage calculation time.
adjust ray caster, so it can handle any resolution (others than sqares with a size of a multiple of 2).