Fixture object is cached in Magento registry

Currently app/code/community/EcomDev/PHPUnit/Test/Listener.php stores the fixture objects in the Magento registry. The fixture object is needed after the test run to clean up records that were created. But using the Magento registry is not a good idea as it might be (and should be) reset between test methods.

We'll be submitting a pull request for this with a suggested solution.
