Experimental DB pool + fixed stat overflow on equips

Implemented EXPERIMENTAL DBCP (connection pool), trying to improve
concorrent access to DB. Added door portals on Kerning Square. Fixed
equipments getting stat overflow when upgrading stats. Fixed expiring
pets crashing the client in some cases.

src/net/server/channel/handlers/SpawnPetHandler.java

@@ -30,6 +30,7 @@ import client.inventory.MapleInventoryType;
 import client.inventory.MaplePet;
 import client.inventory.PetDataFactory;
 import client.SkillFactory;
+import java.sql.Connection;
 import java.sql.SQLException;
 import tools.DatabaseConnection;
 import net.AbstractMaplePacketHandler;
@@ -66,10 +67,12 @@ public final class SpawnPetHandler extends AbstractMaplePacketHandler {
                     return;
                 }
                 try {
-                    PreparedStatement ps = DatabaseConnection.getConnection().prepareStatement("DELETE FROM pets WHERE `petid` = ?");
+                    Connection con = DatabaseConnection.getConnection();
+                    PreparedStatement ps = con.prepareStatement("DELETE FROM pets WHERE `petid` = ?");
                     ps.setInt(1, pet.getUniqueId());
                     ps.executeUpdate();
                     ps.close();
+                    con.close();
                 } catch (SQLException ex) {
                     ex.printStackTrace();
                 }