Commander agent can configure

@chriseidhof, this is sort of what I was thinking.  I *think* you could set 'configure_options' to something like `{ 'location': '{{_location_.latlng}}' }`, although I may have the syntax slightly wrong.  Want to try it and see if it works for you?

(@knu, what do you think?  Also, I was trying to access ‘agent’ from Liquid in the AgentControllerConcern with both {{agent.name}} and {{_agent_.name}} and neither seemed to work.  Am I doing it wrong?)