Deprecating Python code with C++ Equivalents.

[cwharris]

Currently we have both python and c++ implementations of several classes, but it would be good for us to not duplicate functionality, especially when there is a risk of that functionality getting out of sync.

We use C++ implementations because it allows us to interact directly with C++ APIs, and because it can be significantly faster when running performance critical code.

We use Python implementations because it allows us to produce run and test code quickly without compiling, and because it allows us to call Python code directly and get better intellesense for that code.

We should discuss ways to combine the best of both worlds while synchronizing and eliminating duplicate functionality.

One way to do this is change are class hierarch from either python or c++ to instead use a c++ base class with python overrides. This can be accomplished using pybind trampolining.