Fire EVENT_TIMER_END_SPAN a bit later

I feels more natural if the event is fired after the action's time and cycle have
been adjusted and EVENT_TIMER_KEYFRAME is fired (if needed).

See discussion on the forum: http://getmoai.com/forums/timing-of-event-timer-end-span-t1713/
Merge pull request #671 from theGoodEvil/fire_event_timer_end_span_later

Fire EVENT_TIMER_END_SPAN a bit later