[Feature wish] More convenient game speed changing

[MarkusRamikin]

Larger - or better yet, configurable - game speed step setting. Going down from 75 to 15 with a step of 3 is a lot of key mashing!

Also, in the original game I could just hold + or - to get to very slow/very fast speed quickly. Would be nice if it worked here too.

EDIT: perhaps pressing control could increase the step, just like with scrolling the view. So if you press ctrl and -, you decrease speed by 15 instead of 3.