QETProject have is own ProjectDataBase, then when the database is
updated, everything that need the database is also updated trough the
signal emitted by the database.
Begin a widget to edit the NomenclatureModel
Add class NomenclatureModel witch is used with QetGraphicsTableItem.
Add ProjectDataBase class, the goal of this class is to store all
information of a project at an instant T to easilly find it. This class
is still in development and not provide all information that she should.