pybind11 wrappings for Color, Euler, Frustum, Line, Plane, Quat, Shear, Random

[cary-ilm]

This completes the wrappings for the non-array Imath classes. The non-array tests in pyBindImathTest.py pass (mostly).

Reminder that the strategy in introducing pybind11 wrappings is to get the current test for the boost-based bindings, src/python/PyImathTest/pyImathTest.py, to execute successfully with the pybind11 bindings. The test has been copied to src/pybind11/PyBindImathTest/pyBindImathTest.py, with the not-yet-succeeding tests commented out, then as the bindings are completed, un-commenting them out to verify the behavior.

A few issues remain:

• Doc strings still need to be ported
• Return values from operators are not all correct, even though the tests pass.
• A few floating-point conversion issues remain as TODO's in the tests