Tony Massé

This is the replace the much simpler but prone to problem simple (and small) random Integer generation. And moved the function to its own `/utils/Identifier.js` file for ease of maintenance....

`generateId` produces very weak IDs. Needs to be replaced by something much more unique and safe

1

I'm proposing to use UUID instead of simple small Integer, as this the current solution is very prone to collision.

with `{x:0, y:0}` in DiagramModel.addLink(). To prevent error message when new link is created. As the link's curve cannot otherwise be drawn properly (as no `x` nor `y` yet defined...