TLS Support

Enables support for TLS enabled docker hosts.
This should work exactly like the client.

Also adds support for Docker 1.3, which no longer shows the docker storage path on the GET /info endpoint.
As such, you can provide a --docker-root path, which defaults to /var/lib/docker.
If you are on < docker 1.3 we do still try to get the root path from GET /info, so this should continue to work normally.