- Use declarative for SQLAlchemy models.

- To allow for easier integration with 'repoze.workflow', add a
  'status' attribute to the Content class.

- Use 'pyramid_deform' instead of our own Form class.  Also, implement
  CSRF protection.

- Add an item to control panel that integrates with 'pyramid_exclog'.

- Move navigation related functionality out of TemplateAPI and into snippets.
