courier prime non-APL font; language-[not APL] as nonAPL font

[rikedyp]

• Unspecified code blocks and inline code use the APL font
• Class language-APL and language-apl use the APL font
• Code blocks and inline code with class language-* for anything other than APL use the nonAPL code font
• The nonAPL code font is now Courier Prime, included with license and copyright notice

fixes #55

[abrudz]

Wrong font. Courier Prime is designed specifically for screenplays. There are lots of good free coding fonts, but if we really want to go with a Courier, use Courier Prime Code.

[FionaDyalog]

Courier Prime Code is not serif-y enough – it needs to be really obvious that it is not APL385 with even short extracts (Courier Prime is OK).

It does not have to be a courier-based font, but does need to be monospace with serif. Let's discuss offline.

[rikedyp]

Go font was proposed.

Looks a bit large so I'm also decreasing the font size by .1rem.

[abrudz]

Sizes should be adjust relative to the current size, not the root size. Otherwise, code in headings, footnotes, etc. will be wrong.

[rikedyp]

so just em, not rem

[rikedyp]

I've adjusted for this non-APL code issue only, but might be worth a separate issue to audit and clean up the CSS in general. Adjusting font sizes relative to the current size, if best practise, sounds like it will need care to take account of cascading effects.