[C] Call WorldSaveEvent on /save-all. Fixes BUKKIT-3681

Calls WorldSaveEvent when a world is saved (for example with /save-all). Tested with https://github.com/Pheasn/WorldSaveTracker and working.

Binary for testing here: https://googledrive.com/host/0ByrehF-VA20bYUlKN1JRdU13N1U/generalbin/tracker.jar