little bit of work in the docstrings
cherry-picked commit by palli: f648a4b2d74e8b041ac8adace9060f664dba35f0
a conflict had slipped through
A little more docstrings
Continued doc for pynag/Parsers
Some more docstrings
Finished first pass on docstrings
Merge with master
Try to fix doctests, and remove those that were not tests
Merge remote-tracking branch 'upstream/master' into sphinx-doc-test
Merge pull request #136 from ppepos/sphinx-doc-test

Good chunk of Sphinxish docstrings