On Lut loading, 1D luts are checked to determine if the underlying
transform represents 'identity'. If so, they are skipped during op
generation. This is particularly useful when working with 3D luts
that have shaper luts, which are often left as identity.

This check is added to the lut1d-finalize call, which takes a
'tolerance' as an arg as the underlying file quantization is file
dependent.

Commits:
177bf402f6ff95ba70224aa4466e7773c5a89f96

-- Jeremy