Add support for new docker restart policies

Docker deprecated the "-r" switch for the docker daemon.
Since docker 1.2 every container can now have it's own restart policy.

Module restart_policy option defaults are the same as the docker command defaults.
Needs docker-py >= 0.5.0.
Settings get ignored when used with a lower docker-py version. Tested it with docker-py 0.3.2. 
Works for me, I'll get those changed after merging.

I had looked at check_dependencies last night and was thinking about how to move version checks into there and still be obvious  about where each check was needed so this will fit in with that.