[Ci-users] duffy requests

1) Public source code 2) Arbitrary metadata (could be JSON or just a blob) like /Node/get/?key=blah&metadata=<base64 encoded json> Then a new /InventoryExt verb that returns JSON like:

[ { "name": "n49.pufty", "ssid": "abcde", "metadata": "<base64 encoded json>" }, { "name": "a29.pufty", "ssid": "abcde", "metadata": "<base64 encoded json>" } ]

3) Also add a new option to /get/ named "longpoll" which means the machine is automatically deallocated when the requester's TCP connection closes. This would help ensure that e.g. cancelling the job or a Jenkins restart etc. automatically deallocated the machine