Initial commit of some of Marshall's existing code

This is an initial commit based on my existing python code for
working with MCFOST files. This includes a *partial, incomplete*
reworking of the parameter file parsing code to have a better interface
and to add 2.17 compatibility. Certainly buggy in several parts.
Initial documentation framework using Sphinx.

Very rough framework for documentation.
Minor updates to documentation.
Cleanup of plotting code

Some work to make the plotting code take advantage of the new object
interface to Paramfiles.
Merge pull request #1 from mperrin/master

First steps