Removed the parameter use in database drivers' _close() and added a default _close() method in CI_DB_driver + some changelog fixes
diff --git a/system/database/drivers/interbase/interbase_driver.php b/system/database/drivers/interbase/interbase_driver.php
index 1b18de8..c457f63 100644
--- a/system/database/drivers/interbase/interbase_driver.php
+++ b/system/database/drivers/interbase/interbase_driver.php
@@ -472,12 +472,11 @@
 	/**
 	 * Close DB Connection
 	 *
-	 * @param	resource
 	 * @return	void
 	 */
-	protected function _close($conn_id)
+	protected function _close()
 	{
-		@ibase_close($conn_id);
+		@ibase_close($this->conn_id);
 	}
 
 }