I think its weird that the name has `SparkListener` as a prefix.  I think that in those cases where its ambiguous, the fully qualified class name can disambiguate.  I realize I may be a little on this, since there is already `SparkListenerStageSubmitted`.  But  I think if we do really want the prefix, then we should at least be consistent and put it on all the events.  Considering that would break the API anyway, I'd vote we drop the prefix from everything.