Hroot is noisy

[kofalt]

An example run:

$ hroot run bash
Running example.com/ubuntu/12.04
Opening source repository
Connecting to docker /var/run
Docker already has example.com/ubuntu/12.04 loaded, not importing from graph.
Launching container.
root@7a00d1623d1c:/docket# exit
Exporting to docker cache: example.com/ubuntu/12.04 latest
[DEPRECATED] The format 'CONTAINER [REPOSITORY [TAG]]' as been deprecated. Please use CONTAINER [REPOSITORY[:TAG]]
90061cfc10d28f1993987d11cadf61be8d0752f05c184dfdff46efd95975c6ca
7a00d1623d1cfaae9c3d00e84c7a6e221cf29bf83c2cc6a979ea99dbe190afd1

That's nine lines of flak you probably don't care about. Proposal: setting key and flag quiet that only print errors from non-container output.