Query daemons across all hosts with `./bin/phd status --all`.

Summary: Ref T4209. Currently, `./bin/phd status` prints a table showing the daemons that are executing on the current host. It would be useful to be able to conventiently query the daemons running across all hosts. This would also (theoretically) make it possible to conditionally start daemons on a host depending upon the current state and on the daemons running on other hosts.

Test Plan:
```
> ./bin/phd status --all
ID      Host                    PID     Started                     Daemon                                            Arguments
   18          phabricator     6969   Jun 12 2014, 4:44:22 PM     PhabricatorTaskmasterDaemon
   17          phabricator     6961   Jun 12 2014, 4:44:19 PM     PhabricatorTaskmasterDaemon
   16          phabricator     6955   Jun 12 2014, 4:44:15 PM     PhabricatorTaskmasterDaemon
   15          phabricator     6950   Jun 12 2014, 4:44:14 PM     PhabricatorTaskmasterDaemon
   14          phabricator     6936   Jun 12 2014, 4:44:13 PM     PhabricatorGarbageCollectorDaemon
   13          phabricator     6931   Jun 12 2014, 4:44:12 PM     PhabricatorRepositoryPullLocalDaemon
```

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T4209

Differential Revision: https://secure.phabricator.com/D9497