LeoServer.py: Add current commander info in get_ui_states command

[boltex]

For leoserver : Add the current commander info to the get_ui_states command return data. This will enable more flexible UI interaction in LeoInteg or any other clients connected to it.

[edreamleo]

@boltex I'll do this issue immediately.

[boltex]

@edreamleo I'll make some more additions to the server. I spoke to soon in thinking those modifications were enough to implement detached body panes in LeoInteg. (or other external clients) This will take me a day or so.

(I'll make a new branch and pull request.)

[edreamleo]

@boltex No problem. Take as much time as you want.