docker: Notice when container is no longer running
docker: Notice when container is no longer running

Aside from calling edward status, the Status function is called
frequently by the runner. We utilize that to close the done channel
which is normally done by Stop.

Probably the less hacky way to implement this is to see how commandline
deals with this scenario. (I think it might use logic in status.go getState)

See for more info: https://yext.slack.com/archives/CDW79LMCJ/p1541712100011800

yext/edward,yext/edward,yext/edward