Merge request of new tool docker

[Cyrille Berger Skott]

Hi,

Found three other issues:
* if you close the tool docker, there is no way to get it back (short of 
restarting the application)
* if there is only one tool widget, it should not show the lock/tab button, 
and only show tool options, no group widget
* File > close --> you get a "tool docker"

I am a bit uncovinced by the so call "tool bar docker", I understand the idea, 
but then I would suggest to not give the choice to the user and to always have 
it, make it movable and use a single line.
Right now it feels unnatural.

-- 
Cyrille Berger Skott