chore(app-emulation/docker): cleanout old ebuilds
feat(app-emulation/docker): cros-workon'ify

Use the symlink and -9999 pattern. This pull from crosbymichael's WIP
0.11.0 release branch but will make it easy to bump once the final
release is in.
bump(app-emulation/docker): docker-0.11.0 final
Merge pull request #588 from philips/docker-0.11.0

bump to docker 0.11.0