google-map-marker double-registers event listeners when map is set

[Jeffrey J. Bryan]

The _mapReady() method unnecessarily calls _clickEventsChanged() and _mouseEventsChanged().

[Eric Bidelman]

This is by design. It waits for the maps api to be ready before adding the listeners. When _clickEventsChanged() gets called the first time at bootup, this.maps won't be set yet and https://github.com/GoogleWebComponents/google-map/blob/master/google-map-marker.html#L263 won't get called.