Initial checkin - note that in this state, it's producing an ipython
tb failure.

Use this as a test case to fix the ultratb bug.
improve rst_directive and fix bug in unknown_cell
Rename to more generic name - nbconvert.
Added an equation example to test the ..math:: directive.
Added heading cell converter. Also changed the down-parser for output to html (from looking for <div> and </div> to <body> and </body>.
Reverted call to "rst2html.py" to "rst2html".
Added "work_flow.txt" which has a summary of how to interact with IPython github code.
first pass of docutil writer/translator for rst to ipython notebook conversion.  It is based on the html4css1 writer/translator and as such has some vestigial code hanging around while I continue to figure out how everything fits together
removing accidentally committed pyc file
some cleanup
work-a-round filter out paragraphs generated from ref errors that occur because docutils does not recognize the sphinx ref directive
adding in a copy of a sci-kit learn tutorial I have been using for development
refactored nbconvert, nosetest pass

joint work with @jeremiahbuddha and @aisipos
Updated location of test notebook in tests/test_simple.py.
rebase