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
Switched travis IRC channel to #nupic-hackers.

This is a very simple config change for Travis-CI, so bypassing the PR process to avoid unecessary noise.
Merge branch 'master' of github.com:numenta/nupic into sp_boost_bugfix