Store more beautifier options to config

[kassi]

Hi, I like your work! It's the only extension working with current Safari without having to install some special other plugins...

I did some additions to save all the options to the config. Go through the commits - I also refactored my code, maybe easier to understand step by step.

Initially I wanted to take a look at how to implement saving the selected font and size to config at all, because it doesn't work in my installed version. After I forked, I realized, that code for it already exists and fortunately works here. Don't know the differences between the officially installed version and the source, but I can also live with my fork :-) However, we have to check. However, after I saw that the other options were missing, I added them.

Greetings from Germany KSi