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/client/MapleRing.java

@@ -51,7 +51,7 @@ public class MapleRing implements Comparable<MapleRing> {
     public static MapleRing loadFromDb(int ringId) {
         try {
             MapleRing ret = null;
-            Connection con = DatabaseConnection.getConnection(); // Get a connection to the database
+            Connection con = DatabaseConnection.getConnection();
             PreparedStatement ps = con.prepareStatement("SELECT * FROM rings WHERE id = ?"); // Get ring details..
             ps.setInt(1, ringId);
             ResultSet rs = ps.executeQuery();
@@ -60,6 +60,7 @@ public class MapleRing implements Comparable<MapleRing> {
             }
             rs.close();
             ps.close();
+            con.close();
             return ret;
         } catch (SQLException ex) {
             ex.printStackTrace();
@@ -102,6 +103,7 @@ public class MapleRing implements Comparable<MapleRing> {
             ps.setInt(2, ringID[0]);
             ps.executeUpdate();
             ps.close();
+            con.close();
             return ringID[0];
         } catch (SQLException ex) {
             ex.printStackTrace();