Change ol.Object event name syntax

'changed' to 'change' and '<attribute>_changed' to 'change:<attribute>'.

examples/geolocation.js

@@ -31,7 +31,7 @@ var marker = new ol.Overlay({
 // bind the marker position to the device location.
 marker.bindTo('position', geolocation);
 
-geolocation.addEventListener('accuracy_changed', function() {
+geolocation.on('change:accuracy', function() {
   $(marker.getElement()).tooltip({
     title: this.getAccuracy() + 'm from this point'
   });