Clarify that gear is async.
Actually remove() needn't be async.
Improve the DockerImageBuilder so it cleans up after itself.
Docker doesn't like '-' in image names.
New tests, and reorganize existing DockerImageBuilder usage slightly.
Fix indentation.
Wait until unit is running before removing it.
More accurate implementation of what I'm trying to test.
Try doing Dockerfile another way.
GearClient.remove() should only fire once unit has actually stopped.
Better test for docker inspect.
Better explanatory comment.
Disable cleanup for now.
Lint fixes.
Install new location of docker files.
Merge pull request #410 from ClusterHQ/gear-is-async-396

Gear.remove now fires its deferred after the unit has been removed

Author: @itamarst
Reviewer: @wallrj

Fixes #396