* Group "transform" attributes.
* Round "transform" attribute values.
* Remove unused stroke attributes.
* Add an "eraser" class attribute to let user retrieve the element role.
* Pass Clutter color and Pango fontDescription objects to elements, not strings.
* Do not use the color format '#rrggbbaa' in svg since it is not supported in GNOME 3.24.
* It is no longer required to clamp the setting value in area.js.
* Add a "range" property, completed with another 'step' property, to PixelSpinButton in order to directly initiate the lower and upper values of the adjustment from the relevant setting range.
* Not related: fix an inversion between Pango and Cairo in element.js.