Workaround marked, use typogr for all enhancement

marked [escapes quotes][1] itself and there currently isn't a way to disable it.
Since typogr doesn't (and shouldn't) work with escaped HTML entities, replace
them ourselves. Quotes are now rendered as smart quotes.

[1]: https://github.com/chjj/marked/blob/84a9be252dbe63530a26a80eb49ef9442f2dd1e9/lib/marked.js#L994-L1001