I've committed this in Rev1118.
As a compromise, I left in the old EVENT_WAYPOINT as well as adding ARRIVE/DEPART to allow server ops some time to change their scripts.
All current occurrences of EVENT_WAYPOINT should be changed to EVENT_WAYPOINT_DEPART to maintain the old functionality.
I expect EVENT_WAYPOINT will be removed in a couple of weeks, so update those scripts now
