This reprensents some generic features that would need to be implemented
in brmbar-gui-qt4 to have a fully fledged user interface.

. User management
	- Add user
		- Name
		- Barcode
	- Delete user
	- Forbid negative credit
- Stock management
	- Allow overriding item barcodes
	- Group quantity changes in a single transaction (for single receipt, many stock)
	- Support for directly paying for stocked items from user credit
- Statistics
	- Users with debt
	- Pretty chart
	- Fix "inventory value" computation
- Advanced inventory management
	- Mass quantity/cash corrections ("inventura" mode)
	- Integrated brmbar overflow support
- Mail/IRC notifications (e.g. receipt withdrawals, monthly balance, ...)