Some more backwards incompatible changes (minor though), also a ton of small cleanup.

onPluginEnable(PluginEvent event)   -> onPluginEnable(PluginEnableEvent event)
onPluginDisable(PluginEvent event)  -> onPluginDisable(PluginDisableEvent event)
onVehicleUpdate(VehicleEvent event) -> onVehicleUpdate(VehicleUpdateEvent event)
onWorldSave(WorldEvent event)       -> onWorldSave(WorldSaveEvent event)
onWorldLoad(WorldEvent event)       -> onWorldLoad(WorldLoadEvent event)

src/main/java/org/bukkit/event/server/ServerCommandEvent.java

@@ -7,7 +7,7 @@ import org.bukkit.event.Event;
  * Server Command events
  */
 public class ServerCommandEvent extends Event {
-    public ServerCommandEvent(final Type type) {
-        super(type);
+    public ServerCommandEvent() {
+        super(Type.SERVER_COMMAND);
     }
 }