Added possibility to pass custom database objects to DB Forge and DB Utilities

Also, their  property is no longer public and the utility class no longer extends CI_DB_forge.
diff --git a/system/database/drivers/mysql/mysql_forge.php b/system/database/drivers/mysql/mysql_forge.php
index ea32077..019f6d3 100644
--- a/system/database/drivers/mysql/mysql_forge.php
+++ b/system/database/drivers/mysql/mysql_forge.php
@@ -74,11 +74,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
 	}
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index 914d6a2..088a6a0 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.php
@@ -74,11 +74,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
 	}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php
index dc856ed..2add7d2 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php
@@ -88,11 +88,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
 	}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php
index b5235d2..1e4d2ac 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php
@@ -71,11 +71,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		if (version_compare($this->db->version(), '9.0', '>'))
 		{
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
index 4148262..2e5f123 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
@@ -68,11 +68,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		if (version_compare($this->db->version(), '3.3', '<'))
 		{
diff --git a/system/database/drivers/postgre/postgre_forge.php b/system/database/drivers/postgre/postgre_forge.php
index ad26763..425622f 100644
--- a/system/database/drivers/postgre/postgre_forge.php
+++ b/system/database/drivers/postgre/postgre_forge.php
@@ -64,11 +64,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		if (version_compare($this->db->version(), '9.0', '>'))
 		{
diff --git a/system/database/drivers/sqlite3/sqlite3_forge.php b/system/database/drivers/sqlite3/sqlite3_forge.php
index 7ba0f7b..e9b91e9 100644
--- a/system/database/drivers/sqlite3/sqlite3_forge.php
+++ b/system/database/drivers/sqlite3/sqlite3_forge.php
@@ -54,11 +54,12 @@
 	/**
 	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		parent::__construct();
+		parent::__construct($db);
 
 		if (version_compare($this->db->version(), '3.3', '<'))
 		{