Refine front-end styles

[jasmussen]

This is a meta issue to ensure that the front-end looks like the back-end, which includes refine all markup.

This is separate from #1315, in that it deals largely with the blocks we have and how they render out of the box.

Related:

• Button block markup in the front-end #1642
• Drop cap class not extended to front end when saved. #1417
• Encoding issue with dash in quote source  #801

[mtias]

Closing as it's a bit vague. If we have concerns with individual blocks or markup implementations, we should create specific issues. We will do a review of all blocks in any case at various points leading to eventual core merge.