Update dockerpty; stub it out in tests

Its current behaviour occasionally causes tests to hang; until this is
resolved, we'll stub it out. We weren't testing the output of 'run'
anyhow (though we should be).
Support for host address in port bindings (Closes #267)
Support volumes_from option

Signed-off-by: Satoshi Amemiya <rail.sky@gmail.com>
Merge pull request #236 from rail44/feature-support-volumes-from

Support volumes_from option