feedback on multi-figure-manager

Hello everybody

Its been a couple of weeks an I was wondering if anybody has feedback for me.

I changed the description on the PR to be more precise.
At the begining I called it tabbed gtk3 figuremanager but it is more a
multi-figure-manager with the first implementation in gtk3.



Y yo que culpa tengo de que ellas se crean todo lo que yo les digo?

-- Antonio Alducin --