Fix genty being used on a parent class and base class defined in separate files and run with a test runner like nose.

Genty needs to not collect tests that have already been genty_generated to avoid expanding already expanded tests.
Fix linting error from new tox/pylint.
Add test coverage for subclass + metaclass fix.
Fix keywords in setup.py. keywords expects an iterable and we passed in a string, so the keywords were g,e,n,t,y, ,t,e,s,t,s,...
mock.patch.object works by removing params from a method's argspec (the mocked objects), but then calling the patched method with the correct number of args.

This breaks genty because genty relies on the method signature as defined when the class is wrapped with @genty. We then replace the method with a lambda which takes the wrong number of args. This patch fixes the problem by taking *args in the lambda.
Disable bogus pylint bad super call error.
Allow importing directly from genty instead of box.test.genty
Bump version to 0.3.0. Prepare to deprecate namespace packaged version.
Update version in which breaking change will occur. Import genty from genty, not box.test.genty in test_genty. Fix typo in README.
Update README rst formatting.
Fix announcement.
Fix a bug that would cause genty to fail when trying to expand tests defined by the metaclass.
delattr(cls, attr) fails when attr is defined by the metaclass with AttributeError. Just catch that error and pass.
Disable bogus bad-super-call pylint warning.
Bump version to 0.3.1
Fix typo in README.

excerising -> exercising