Consider removing Typekit Fonts

[davidfischer]

Currently, readthedocs.org uses Adobe Typekit to load some fonts. These fonts are Inconsolata, a SIL open font licensed monospace font and four versions of FF Meta, a proprietary font that is also used on the Read the Docs logo.

I know there is some redesign work going on but I think we can get a quick win by swapping these fonts to using a native font stack for a couple reasons.

• Read the Docs won't look different in development (where TypeKit isn't available) vs production
• There are performance improvements from not having to download fonts although they aren't huge on readthedocs.org (they're much larger on the RTD theme). It's ~115kb and can be around 1/3 of a second. If you see the "flash of unstyled text" when loading readthedocs.org, this is why.
• Some users consider Typekit a "tracker" and are concerned about its security and privacy implications. Regardless of your thoughts on that subject, it is 3rd party code we are currently executing on Read the Docs. If we don't use these fonts, we don't need TypeKit.

The biggest downside is that the Read the Docs logo will use a different font than the rest of the site.

I'd be happy to put together a small PR swapping to a native font stack. I believe it will only touch 1 file and be only a few lines. Thoughts?

I detailed some of my thoughts on native font stacks in a ticket on the RTD theme (readthedocs/sphinx_rtd_theme#524).