Implement test SingleComponentRepo.test_04_rm_standard_layout().
Fix the component-depth CLI logic for `evnadmin create`.
Add support for running a single test by class name.
Implement TestMultiComponentRepo.test_01_creation().
Tweak test_04_rm_standard_layout() (non-functional change).
Ensure non-(single|multi)-component repositories can still be created.

These repositories will have a component depth of -1.
Fix typo: s/repositorydirectory/repository directory/.
Add error StandardLayoutTopLevelDirectoryCreatedInMultiComponentRepo.
More fixes for component-depth logic.
Tweak how error messages are asserted.

Ensure something useful gets printed to the screen.
Add more tests for multi-component and no-component-depth repos.

All tests are currently passing.