Fenced code blocks: Make language info string parsing more spec-conform.
Handle leading whitespace in fenced code blocks.
Add language class to fenced code block output.
Do not escape HTML in fenced code blocks twice (done on rendering).
Fix display of code block language where none is given.
Toy around with whitespace inside of fenced code blocks.
Do not merge code blocks into paragraphs.
Don't append two lines to the document globally.
Simplify code block content storage.
Finish fenced code block parsing.

It all came down to newlines in the end.