Preparing release 3.0.4
Back to development: 3.0.5
Workaround KeyError for unicode TALES expressions
Add test for TALES expression unicode KeyError
Update changelog with TALES expression cause.
explicitly include plone.stringinterp
Mail action: if string interpolation of recipient gives several times
  the same email address,
  the email is sent only once to this recipient.
Do not use assertIn since it is not supported on Python 2.6.
Replace deprecated test assert statements.