nova double: list server filters and run server.
Implemented filters by status and name (others not implemented, but
probably also not needed), as well as creating a server (RunServer).
Added a few needed things: serverByName and generateUUID + tests.
With this, the nova double will be up-to-date with the nova client
and functional.
R=fwereade, rog
CC=
https://codereview.appspot.com/7073060