Drop the use of nose in favor of testrepository. Set up the gitignore
rules for the output files.
Add coverage reporting to test jobs.
Update tox.ini so the default environments make sense so it is possible
to just run "tox" for local development.
Change-Id: Ieeffdde3bb8a1869af01f5be2bc682a1a834ba13
Signed-off-by: Doug Hellmann <doug@doughellmann.com>