testtools 1.3.0

Changes
-------

* Fixed our setup.py to use setup_requires to ensure the import dependencies
for testtools are present before setup.py runs (as setup.py imports testtools
to read out the version number). (Robert Collins)

* Support setUpClass skipping with self.skipException. Previously this worked
with unittest from 2.7 and above but was not supported by testtools - it was
a happy accident. Since we now hard depend on unittest2, we need to invert
our exception lookup priorities to support it. Regular skips done through
raise self.skipException will continue to work, since they were always caught
in our code - its because the suite type being used to implement setUpClass
has changed that an issue occured.
(Robert Collins, #1393068)