Possibility to define buttons size and style for each toolbar

[lypwig]

This will allow the user to heavily customize the UI.

The main advantage in my opinion will be to be able to set large icons for toolbars used very often, and small icons for the others. It's even more interesting when working with customized toolbars.

That could look like this:

The resulting toolbar shares ideas in common with what is suggested in #14, but with less work to do, so maybe it's a good compromise if you don't have too much time to spend on it.

Preference UI suggestion: an array with the list of all toolbars:

Toolbar name	icon style	icon size	nb. rows
File	text	big	1
View	icon	big	2
Sketcher	icon	small	2
Geometries	icon + text	small	3
Constraints	icon + text	small	3
...	...	...	...

Where the first row (header) and the first column are not editable, and all the other cells are a drop-down list used to select the desired option.