TODO

* Finish prosecuting bugs in the Google Code tracker;
  either develop test cases for them or deem them invalid/unreproducible/wontfix
  (new bugs should go in the github tracker).  Also look for bugs filed against
  the PHP implementation (such as in the Textpattern tracker); those bugs
  may also exist in this implementation.

* Improve test coverage (use coverage stats in docs/coverage/index.html).

* Improve documentation, both of the code and Textile syntax.
  The previous version of pytextile had excellent inline documentation;
  similarly, docstrings such as "What does this do?" should be improved.

* Address outstanding architectural issues:
  The Textile class has a large number of public methods which are, in fact,
  not intended to be called by the public.
  Also, some parameters are set in __init__(), while others are set in
  textile().
  Because various instance variables get set while text is being processed,
  a Textile object cannot be reused--that is, it is not possible to set up
  a Textile object with the desired parameters, and then use it repeatedly
  to process multiple strings, because parameters such as the shelf do not
  get reset between calls to textile().

* If we want to re-implement sanitization or validation, it should probably be
  done with html5lib.