Update docs. Correct errors reported by setup.py build_docs. Add rest interface and link to rest doc to features page. Add link to xmlrpc doc to features page. Add rest doc to index. Update rest doc, hopefully clarify confusing use of parameters in patch action section. Fix code examples in "Adding new rest endpoints" section. Fix example adding import of exception.

Docs
====

.. toctree::
   :maxdepth: 2

   docs/features
   docs/installation
   docs/upgrading
   docs/FAQ
   docs/user_guide
   docs/customizing
   docs/admin_guide
   docs/xmlrpc
   Design (original) <docs/design>
   docs/developers
   docs/tracker_templates
   docs/acknowledgements
   docs/license