Initial documentation of TP.py for Doxygen.

First pass through the temporal pooler interface, updating docstrings so they are formatted for doxypy to convert into doxygen comments before using to build docs with doxygen.
Ignoring generated html. Preventing LaTeX build.
Preventing LaTex doc build.
Using default location of doxypy.

Also added DOCS.md readme with instructions on building docs.
Adding more @param docstrings for TP constructor.
Merge pull request #461 from rhyolight/doxygen

Doxygen configuration & TP.py docs