Zope-testing

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

- Add back ``DocFileSuite``, ``DocTestSuite``, ``debug_src`` and ``debug``
BBB imports back into ``zope.testing.doctestunit``; apparently many packages
still import them from there!

- Deprecate ``zope.testing.doctest`` and ``zope.testing.doctestunit``
in favor of the stdlib ``doctest`` module.

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

- Fix missing imports and undefined variables reported by pyflakes,
adding tests to exercise the blind spots.

- Cleaned up unused imports reported by pyflakes.

- Add two new options to generate randomly ordered list of tests and to
select a specific order of tests.

- Allow combining RENormalizing checkers via ``+`` now:
``checker1 + checker2`` creates a checker with the transformations of both
checkers.

- Fix tests under Python 2.7.

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

- Fix test failures due to using ``split()`` on filenames when running from a
directory with spaces in it.

- Fix testrunner behavior on Windows for ``-j2`` (or greater) combined with
``-v`` (or greater).

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

- Remove hotshot profiler when using Python 2.6. That makes zope.testing
compatible with Python 2.6

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

- Avoid hardcoding ``sys.argv[0]`` as script;
allow, for instance, Zope 2's `bin/instance test` (LP407916).

- Produce a clear error message when a subprocess doesn't follow the
``zope.testing.testrunner`` protocol (LP407916).

- Avoid unnecessarily squelching verbose output in a subprocess when there are
not multiple subprocesses.

- Avoid unnecessarily batching subprocess output, which can stymie automated
and human processes for identifying hung tests.

- Include incremental output when there are multiple subprocesses and a
verbosity of ``-vv`` or greater is requested. This again is not batched,
supporting automated processes and humans looking for hung tests.

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

- Allow testrunner to include descendants of ``unittest.TestCase`` in test
modules, which no longer need to provide ``test_suite()``.