Wed bug fixe

Created by: udoman

-Added validation for Edit, Add Product, made sure fields are proper -Accounted for improper cashier initials to prevent complete transaction -Added invalid product id upon search -Implemented ProductCode logic as well as productId. (both for edit and add) -Delete Category should delete -You should not be able to delete the current cashiers set (still wonky, works except for when you add a new cashier and set) -too tired to fix(will do tomo hopefully) -Deleted logo images stuff that is not used