openlayers/ol3 — pull request #658 by twpayne (2013-04-25 14:58:05+00:00)
Title: ol.Object events

This PR adds a few more functions to `ol.Object` exposing the `goog.events` API:

* `on` has been updated to return the listener key
* `unByKey` (same as `goog.events.unlistenByKey`)
* `onOnce` (same as `goog.events.listenOnce`)