Fix Craft Entity constructors and toStrings.

Also, standardise getHandle and clean up in general.
getHandle is now using the 'entity' member variable instead of
super.getHandle, as this reduces the number of chained calls needed.

src/main/java/org/bukkit/craftbukkit/entity/CraftMinecart.java

@@ -26,62 +26,59 @@ public class CraftMinecart extends CraftVehicle implements Minecart {
         }
     }
 
-    protected EntityMinecart minecart;
-
     public CraftMinecart(CraftServer server, EntityMinecart entity) {
         super(server, entity);
-        minecart = entity;
     }
 
     public void setDamage(int damage) {
-        minecart.setDamage(damage);
+        getHandle().setDamage(damage);
     }
 
     public int getDamage() {
-        return minecart.getDamage();
+        return getHandle().getDamage();
     }
 
     public double getMaxSpeed() {
-        return minecart.maxSpeed;
+        return getHandle().maxSpeed;
     }
 
     public void setMaxSpeed(double speed) {
         if (speed >= 0D) {
-            minecart.maxSpeed = speed;
+            getHandle().maxSpeed = speed;
         }
     }
 
     public boolean isSlowWhenEmpty() {
-        return minecart.slowWhenEmpty;
+        return getHandle().slowWhenEmpty;
     }
 
     public void setSlowWhenEmpty(boolean slow) {
-        minecart.slowWhenEmpty = slow;
+        getHandle().slowWhenEmpty = slow;
     }
 
     public Vector getFlyingVelocityMod() {
-        return new Vector(minecart.flyingX, minecart.flyingY, minecart.flyingZ);
+        return getHandle().getFlyingVelocityMod();
     }
 
     public void setFlyingVelocityMod(Vector flying) {
-        minecart.flyingX = flying.getX();
-        minecart.flyingY = flying.getY();
-        minecart.flyingZ = flying.getZ();
+        getHandle().setFlyingVelocityMod(flying);
     }
 
     public Vector getDerailedVelocityMod() {
-        return new Vector(minecart.derailedX, minecart.derailedY, minecart.derailedZ);
+        return getHandle().getDerailedVelocityMod();
     }
 
     public void setDerailedVelocityMod(Vector derailed) {
-        minecart.derailedX = derailed.getX();
-        minecart.derailedY = derailed.getY();
-        minecart.derailedZ = derailed.getZ();
+        getHandle().setDerailedVelocityMod(derailed);
+    }
+
+    @Override
+    public EntityMinecart getHandle() {
+        return (EntityMinecart) entity;
     }
 
     @Override
     public String toString() {
         return "CraftMinecart";
     }
-
 }