Graphics tablet/pen

@azkaz & @daveywilson @wenlai @John7 @NicKP @Bebop

please see
Contest: Can PL be used to simulate lighting from flash for portrait shots ?! - #30 by Wolfgang

I would like to use my Wacom tablet more often, but using Strg/CRTL + Touchring (set to scrolling
= equivalent to mouse scrolling) for to change Brush Size / Brush Feathering is a real pain.