- Added property hasSequence to class DB_Model.

This property is used to indicate if the represented table has a primary
  key that uses a sequence (true, otherwise false. Default is true).
- Method insert of DB_Model now checks the property hasSequence.
  If it is true it uses the method insert_id() to return the primary key
  of the row just inserted.
  For any other values the method returns the primary key inserted coping
  it directly from the parameters.
- Set the property hasSequence to false in the constructor of model Prestudentstatus

application/models/crm/Prestudentstatus_model.php

@@ -1,7 +1,7 @@
 <?php
+
 class Prestudentstatus_model extends DB_Model
 {
-
 	/**
 	 * Constructor
 	 */
@@ -10,5 +10,6 @@ class Prestudentstatus_model extends DB_Model
 		parent::__construct();
 		$this->dbTable = 'public.tbl_prestudentstatus';
 		$this->pk = array('ausbildungssemester', 'studiensemester_kurzbz', 'status_kurzbz', 'prestudent_id');
+		$this->hasSequence = false;
 	}
-}
+}