Fix: Better warning message. To lock install, recommanded solution is having an install.lock file, not deleting directory.

to show/hide this bloc

Fix: Bad departement name

negative invoices should be done using credit note).

New: add events system in jquery combobox

Fix: uniformize code

have foreign keys with standard tables. This creates
dependencies and instabilities of core code. Integrity must be checked
by applications for external modules, not by database.

project must be not be set as limited to customer but must be not linked
to any particular thirdparty