[ENH] - Provide Python interface to work with the outputs of BOONStim

A clean python interface to work with the preprocessing steps of BOONStim would serve as a useful platform on which:

- comparison tests between optimization methdologies can be done using data projected into FEM space
- later use of outputs in analysis can be done

It's likely that this will require some re-organization of the BOONStim outputs and caching directories