API: get list of current active visitors

[mikermcneil]

also need to expose this information on the serverside.

The grouping here is important-- this is asking for the list of curent active visitors for this route. Which could mean a separate page or not, who cares, it's the logical unit we're interested in, since we're probably using the client-side router.

[mikermcneil]

Mast needs to leave the endpoint for the serverside reporting as a configurable field-- even if it's a separate host/server/port. While obnoxious, this allows for side-by-side realtime interactivity (spinning up a separate node server to manage socket connections, for instance, while still relying on the original server to handle basic web traffic)

[mikermcneil]

invalid