Fix #26 and buildout cleanup

- Fix all integration- and doctests
- Fix wrong accessor in DemoLanguage adapter.
- Support Sessions in tests.
- Update createdEvent to use aq_parent of created, copied or moved object
  instead of ``event.newParent`` which is not available on
  ``ObjectCreatedEvent``.
- Some pep8 cleanup and alignment to plone coding conventions.
- Add buildouts for Plone 4.0, 4.1, 4.2 and 4.3
- Add travis integration