GitLab

Swigged python docstrings now include documented return values and type
information or their arguments. They are generated in numpydoc format.
Furthermore, all of the Python app layer docstrings have been changed
to numpydoc format. The filterPythonFiles.py script which helps to
generate the Doxygen Python API docs has been updated to reflect these
changes.

Add relevant tests (that used to fail). This also fixes a subtle bug where
switching functions were not applied when NBFIXes were specified.

(part of the long-term plan of supporting Python 2 and 3 in the same code base
without 2to3)