Switch away from deprecated unittest method names.
More TODO notes.
Minor correction to unball.TempTarget
Fix unit test failures caused by TempTarget

(The context manager for handling atomic mkdtemp+rename extraction)
Clear out easily-fixed flake8 complaints.
Update module docstring to reference GitHub rather than Launchpad.
Add untested support for uncompress.real on Debian-based distros.
Add a safety check in the alias handler.

(May not be needed. Might as well play it safe.)
Silence deprecation warnings in run_test.py
Add a few more TODO notes. (Including more extractors)
If we're closing stdin, stdout, and stderr in tests, also unset DISPLAY.