Fired when a marker is removed from the model.
removeMarker is a namespace for a class of events. Names of actually called events follow this pattern:
removeMarker:markerName. By specifying certain marker names, you can make the events even more gradual. For example,
if markers are named foo:abc, foo:bar, then it is possible to listen to removeMarker:foo or removeMarker:foo:abc and
removeMarker:foo:bar events.