Update of systempreferences table structure and admin script. Contains now a "help...

Update of systempreferences table structure and admin script. Contains now a "help" fields that shows what param is supposed to do what. The params will be in the sample-DB. I've dumped the 3 I know. If there are others, let me know :

INSERT INTO systempreferences VALUES ('template', 'french', 'Template default name. Not used for instance');
INSERT INTO systempreferences VALUES ('autoBarcode', '', '1 or else. If 1, Barcode is auto-calculated');
INSERT INTO systempreferences VALUES ('acquisitions', 'normal', 'normal or simple : will use acquisition system found in directory acqui.simple or acquisition');