Merge thee branch proportional to main

[matj1]

I would like that the functionality in the branch proportional would be availabe by default. I have used this configurator on the branch proportional to create proportional fonts. It seems to work well, so I think that proportional is ready to be merged to main, but I do not know details of the code.

Please, merge the branch proportional to main.

[matj1]

This is better discussed in #25.