Filter containers by status.

A continuation of #7616.
Closes #7616.
Adds `docker ps --filter=status=(restarting|running|paused|exited)` option.

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
whoa I didn't even change that line but I can fix, I was going to make a joke about how I suck at grammar but...