Move initialization out of map service constructor.
Update comment.
Cleanup unused code
Remove awareness of getMarkerByVenueId from main controller.
Fix bug where hover popup displayed when you click pin.

Manually create popups instead of using bindPopup.
Change markers propert to venueMarkerMap.
Refactor managements of popup groups.

Create PopupGroupManager that manages situations where you have only one
popup that can be open in a group.
Create isCurrentVenue method.