Tabs, grid, new UI, more widgets ... and import existing spec :)

Hi !

Here is a list of news :

• hack for the tabs, now working !
• loading already existing spec windows is now working.
• new UI for the spec generation
• added more widgets and ComposableModel
• and finally a halo with only needed options :)

I'm actually working on "sticky" morph. It means your widgets will be moved automatically to the closest grid point

Here is some screenshots :)