Leaflet and ArcGIS now exchanging screen click locations.
Exchanging clicks in Google Maps now mostly working.

Need to remove previous marker as next marker is placed.
Some cleanup on coordinate precision (fixed at 3).

Need to set up event dictionary if initializing from the Setup Pusher Client pane.
All systems responding to map click, including when the user has specified a masher channel in the last accordion pane without opening a companion map system.

Probably should provide a callback in each map hoster to retrieve the event dictionary callbacks.  The current mechanism requires the map hosters to have specifically named methods.
Refactored event dictionary into map hoster.

Restored ArcGIS InfoWindow functionality, while keeping ability to push coordinates to listeners.