Pull Request: https://github.com/imageworks/OpenColorIO/pull/123
Issue: https://github.com/imageworks/OpenColorIO/issues/121

Fixes Error handling in python glue for pyprocessor:

processor.applyRGBA(1)

The last line dies with:

Traceback (most recent call last):
File "", line 1, in
SystemError: error return without exception set

This fixes the error by properly setting the exception type. Also
fixes two other similar issues in PyExponentTransform +
PyGroupTransform.

-- Jeremy