+08-Jul-2008 Janusz Dobrowolski
+# Added validation of entered quantities
+$ /sales/customer_credit_invoice.php
+# Fixed ajax update (0000015) and quantity checks
+$ /sales/customer_delivery.php
+ /sales/customer_invoice.php
+# Fixed invalid voiding sales invoice/delivery/credit (0000016)
+$ /sales/includes/db/sales_delivery_db.inc
+ /sales/includes/db/sales_invoice_db.inc
+ /sales/includes/sales_db.inc
+# Fixed setting document date to Today()
+$ /sales/includes/cart_class.inc
+