Mailinglogger

-------------------

- Handle the situation where the temporary file used by a
:class:`SummarisingLogger` is deleted from underneath it.

-------------------

- Add support for including messages logged at a lower level in a
summary email but only triggering the sending of that email when a
message at a higher level is logged when using
:ref:`SummarisingLogger <record-and-send-different>`.

-------------------

- Add ``X-Log-Level`` header to emails sent. For
:class:`MailingLogger`, this is the level of the log message being
emailed. For :class:`SummarisingLogger` this is the highest level of
any of the messages handled.

-------------------

- Fix distribution to include missing files lost through move to Git.

-------------------

- Convert documentation to use Sphinx.

- Convert tests to use `testfixures`__ and `manuel`__.

__ http://packages.python.org/testfixtures/

__ http://packages.python.org/manuel/

- Drop support for "Zope 3".

------------------

- Let the tests also pass in non GMT timezones.

Thanks to Christian Zagrodnick for these changes.