Launching UI for class diagram

[Hyacinth Ali]

To implement a gui and controller to enable the creation of class diagram from touchram ui

[Hyacinth Ali]

References #518

Now, class diagram is registered with core but the weaver is not yet implemented

→ <<cset 9d1c48f14abb>>

[Hyacinth Ali]

References #518

Implementing the scene of class diagram

→ <<cset 72fb63e92e7d>>

[Hyacinth Ali]

References #518

Now, class diagram scene can be launched but with highly limited functionalities. No navigation bar and most of the present buttons are not working

→ <<cset f94c79871edb>>

[Jörg Kienzle]

I think this is done.