Fix for rich comparison and add test for vec3 file

As __cmp__ no longer in Python 3 need to use functools.total_ordering which is in 2.7 and 3.*
  https://docs.python.org/2/library/functools.html#functools.total_ordering
  https://docs.python.org/3/library/functools.html#functools.total_ordering
  Define __eq__ and __lt__ and others are created automatically

Add unittest style for file vec3.py
I agree but I'd rather test what's there before we make any decisions about razing it to the ground given the likely usage numbers of the original code base.