Added support for Backlight dimming on a timeout (RPi UI 16x2/20x4)
When a timeout is set with .SetBacklightTimeout(int minutes) repeated calls to ReportPressed (like menu object in ui module)
the display is dimmed.

when a button is pressed, the display will retrun to its original brightness after any button is pressed. That button press is NOT retruned
So the program wil not act on that button press.