* `context/target` tests must be in groups 1 - 2.
* `context/controller` tests must be in groups 3 - 5.
This makes it easier to efficiently organize groups and balance test runtimes.
* Fix plugin names when loading all plugins.
Add an integration test to verify plugin __package__ and __name__ are correct.
* Make sure filter and test names are unique.
* Remove __package__ test.
On Python 2.x __package__ is not set, but it is on Python 3.x.
