Log Message:
Update py-testtools to 0.9.35.

0.9.35
~~~~~~

Changes
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* Removed a number of code paths where Python 2.4 and Python 2.5 were
  explicitly handled. (Daniel Watkins)

Improvements
------------

* Added the ``testtools.TestCase.expectThat`` method, which implements
  delayed assertions. (Thomi Richards)

* Docs are now built as part of the Travis-CI build, reducing the chance of
  Read The Docs being broken accidentally. (Daniel Watkins, #1158773)