[ENHANCEMENT] Enhance keyword to control the SpinBox

[pcppcp]

Is your enhancement request related to a problem? Please describe.
The Qt Widget SpinBox cannot be easily controlled. Text input (via set text) is not possible and operation using arrow keys is too cumbersome.

Describe the solution you'd like
The keyword Set Text should be applicable to a spinbox to allow values to be entered directly.

Describe alternatives you've considered
No alternatives unfortunately