Make the progress bar speed variable
Make the progress bar speed variable

Arrange for the scales to control the speed of the activity
mode progress bar in gtk3-widget-factory. This will be useful
in demonstrating smoother progress bar animation in the future.

chergert/gtk,Adamovskiy/gtk,jadahl/gtk,alexlarsson/gtk,chergert/gtk,jessevdk/gtk,ahodesuka/gtk,msteinert/gtk,jadahl/gtk,Adamovskiy/gtk,jessevdk/gtk,chergert/gtk,jadahl/gtk,msteinert/gtk,grubersjoe/adwaita,davidgumberg/gtk,alexlarsson/gtk,msteinert/gtk,davidgumberg/gtk,ahodesuka/gtk,Lyude/gtk-,Adamovskiy/gtk,davidgumberg/gtk,chergert/gtk,msteinert/gtk,msteinert/gtk,jigpu/gtk,Lyude/gtk-,jadahl/gtk,jigpu/gtk,Adamovskiy/gtk,grubersjoe/adwaita,davidgumberg/gtk,jigpu/gtk,Adamovskiy/gtk,Adamovskiy/gtk,grubersjoe/adwaita,alexlarsson/gtk,davidgumberg/gtk,Lyude/gtk-,grubersjoe/adwaita,Sidnioulz/SandboxGtk,jigpu/gtk,Sidnioulz/SandboxGtk,alexlarsson/gtk,jigpu/gtk,jessevdk/gtk,ahodesuka/gtk,alexlarsson/gtk,Lyude/gtk-,grubersjoe/adwaita,chergert/gtk,jigpu/gtk,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,grubersjoe/adwaita,jadahl/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,ahodesuka/gtk,ahodesuka/gtk,jessevdk/gtk,Lyude/gtk-,ahodesuka/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,alexlarsson/gtk,jigpu/gtk,chergert/gtk,davidgumberg/gtk,jadahl/gtk,jigpu/gtk,jadahl/gtk,davidgumberg/gtk,Lyude/gtk-,jessevdk/gtk,alexlarsson/gtk,Lyude/gtk-,davidgumberg/gtk,jadahl/gtk,grubersjoe/adwaita,Adamovskiy/gtk,chergert/gtk,msteinert/gtk,alexlarsson/gtk,jessevdk/gtk,chergert/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita