-changed for the VM656A, VM6575 and VM6586 the calibration part(subtract highest and lowest value and then divide).
-default SANE_TECO2_CAL_ALGO value is now 1 for the VM3564 and VM6575
-preview value is now 75 dpi for the VM6575
-Change from WHITE_LEVEL to WHITE_LEVEL_R, WHITE_LEVEL_G and WHITE_LEVEL_B sliders for manual changing calibration value downloaded to scanner.
-Subtraced highest and lowest value from calibration samples before divide by x-2 samples