Split out runner
Rename locations to images to be consistent
Rename payload to commands
Actually run some things through docker
Plumbed through running code for dox.yml
Move to using logging for output
A bunch of output cleanup
Replaced sh with subprocess
Fixed up the unittests to match new organization
Add support for images with tox.ini
Handle extra command line arguments
Skip rebuilding images when we don't need to
Run tests as host user

testr writes files into the local dir, which is cool and works
because of the bind mount - but if we don't run as the same UID
as the executing user, then we'll write unreadable data into
.testrepository.
Indent the text wrap lines hanging
Append extra args with a space for dox.yml