Implemented boat, fixed some event issues with minecarts, and implemented the events for boats that were implemented for minecarts.

src/main/java/org/bukkit/craftbukkit/CraftBoat.java

@@ -0,0 +1,18 @@
+package org.bukkit.craftbukkit;
+
+import net.minecraft.server.EntityBoat;
+import org.bukkit.Boat;
+
+/**
+ * A minecart.
+ * 
+ * @author sk89q
+ */
+public class CraftBoat extends CraftVehicle implements Boat {
+    protected EntityBoat boat;
+
+    public CraftBoat(CraftServer server, EntityBoat entity) {
+        super(server, entity);
+        boat = entity;
+    }
+}