Review: Added Truelight .cub support

Jeremy Selan <jeremy...@...>

Added support for Truelight .cub luts. (Both 1D shaper + 3d lut). 1D
shaper lut currently uses linear interpolation, until something better
comes along.

Note: This checkin tested with a limited number of luts, all written
out from Nuke. If anyone has any non-nuke examples of .cub luts I
would love to test them! Thanks!


-- Jeremy