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/block/BlockDamageEvent.java

@@ -18,7 +18,7 @@ public class BlockDamageEvent extends BlockEvent implements Cancellable {
         super(Type.BLOCK_DAMAGE, block);
         this.instaBreak = instaBreak;
         this.player = player;
-        this.itemstack = itemstack;
+        this.itemstack = itemInHand;
         this.cancel = false;
     }