Maximum value of ushort is 65535, not 65536

[ktgw0316]

[jodygarnett]

Huh, TIFF standard U16 is documented as 0-65535 indeed: TIFF Revision 6.0.

In a TIFF ColorMap, all the Red values come first, followed by the Green values, then the Blue values. In the ColorMap, black is represented by 0,0,0 and white is represented by 65535, 65535, 65535.

This is the kind of change I feel uncomfortable making without downstream integration testing.