Hidpi Display / UI font scaling support

[henning]

On HiDPi Screens (e.g. a resolution like 3840x2160) the fonts are so small they are barely readable, at least on Linux - I didn't try on MacOS or windows so far.
WIth a looking glass i see that Waveedit is s great and super useable app, just the fonts need to be readable to really use it.

I am interested to try to fix this myself, will look at the code to try to understand how to get there...