Add an option to justify rendered text

Nobody has claimed this yet.

Is it possible to add an option to justify rendered text?

I wanted to do this by adding this to the `GitHub2.css` file:

``` css
p {
text-align: justify;
text-justify: inter-word;
}
```

but couldn't get it to work, also tried adding the `text-align: justify;` property in several different places in the same CSS file with no luck, I'm no CSS guru though... :smile:

Maybe I'm missing something, but anyway I think it would be a good idea to add this option in the app's preferences and have it applied to any selected style, for the non-CSS-speaking users. What do you think? I might be able to come up with a PR after some time researching if you like the idea, but if there's some quick and easy workaround it would be really helpful.

Start by examining GitHub2.css and the existing app preferences, then trace how rendered text styles are selected and applied. Check whether text-align is overridden by the selected style. Done means a user-facing preference justifies rendered text across selected styles, with the existing styling behavior preserved.

Written by the indexing model from the issue text.