Implemented #_DOCS_HIDE and #_DOCS_SHOW docstring manipulation logic in 
documentation/library/extensions.py.

We don't need to handle doctest comments (like "# doctest: +SKIP") as Sphinx
has stripped these kinds of comments automatically since 2009:

    https://bitbucket.org/birkenfeld/sphinx/issue/169/strip-doctest-comments-in-rendered-output


git-svn-id: http://music21.googlecode.com/svn/trunk@3493 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Began reimplementing IPython notebook conversion in documentation/.

It may be possible to dump the external nbconvert.py script we've been using
to handle converting IPython notebooks into ReST.

IPython notebooks are relatively simple json files, containing indications
for prose, code and images, all of which can be handled by modules in Python's
standard library (json, base64 etc).  Whether this is really feasible depends
on how complex IPython allows its markdown indications to be...


git-svn-id: http://music21.googlecode.com/svn/trunk@3494 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Renamed documentation/build.py to make.py.


git-svn-id: http://music21.googlecode.com/svn/trunk@3495 5c16147e-a200-11de-b0cc-ab0ad15e60d0