[Feature Request]: Add more keybinds

[Jon-Wesly]

I used to use MComix (https://sourceforge.net/projects/mcomix/)
and I liked the fact that you could just press W to Fit Width, H to Fit Height, B for Best Fit, etc.
It would be nice if you could also just press S to go straight to settings.
Although not necessary, it would be nice to have such conveniences built into OpenComic.