added semantic elements to stylesheets

TODO: update style guide
added text-level stress elements to style guide

TODO:
- replace all instances of Latin expressions in `i` elements with `b` elements.
- add "Document-Level" section to style guide and add document statuses
changed `b[lang]` back to `i[lang]`

foreign languages are more semantically appropriate in the `i` element.

TODO: replace appropriate instances of `&ldquo;...&rdquo;` to `<i>...</i>`
such as scare quotes and mentions
started replacing `&ldquo;` and `&rdquo;` with `<i>` and `</i>`

TODO: finish
finished replacing quote entities with `i` elements

TODO: fix up the punctuation blog post
added quotes section to punctuation blog post
updated more text-level semantics
minor edits to text-level elements in style guide
Merge branch 'develop' into feat#27-stress