Implemented vehicle hooks (some changes will still be made).

src/main/java/org/bukkit/event/vehicle/VehicleEnterEvent.java

@@ -0,0 +1,38 @@
+package org.bukkit.event.vehicle;
+
+import org.bukkit.LivingEntity;
+import org.bukkit.Vehicle;
+import org.bukkit.event.Cancellable;
+
+/**
+ * Raised when a living entity enters a vehicle.
+ * 
+ * @author sk89q
+ */
+public class VehicleEnterEvent extends VehicleEvent implements Cancellable {
+    private boolean cancelled;
+    private LivingEntity entered;
+    
+    public VehicleEnterEvent(Type type, Vehicle vehicle, LivingEntity entered) {
+        super(type, vehicle);
+        
+        this.entered = entered;
+    }
+    
+    /**
+     * Get the living entity that entered the vehicle.
+     * 
+     * @return
+     */
+    public LivingEntity getEntered() {
+        return entered;
+    }
+
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    public void setCancelled(boolean cancel) {
+        this.cancelled = cancel;
+    }
+}