This example shows the scale widget.

The lrscale (resp. tdscale) widget allows to choose a value between a range by moving a horizontal (resp. vertical) slider.

- the 'from' and to parameters define the range of value.
- the init parameter define the initial value.
- the handle parameter allow to specify a variable that can control the widget.
- the return parameter allow to specify a variable that will be bound to the value of the scale when the window is closed.
- the action parameter defines a command that is to be executed when just after the user has changed the value of the scale.
