These are from John Gruber's original markdown test suite, via
Michel Fortin's mdtest.

The html files have been modified slightly in ways that do not affect the
semantics.  For example, entities are used for quotes in text, and
blank lines are omitted between block-level tags.

Trailing blank spaces are removed from lines in raw HTML blocks.

The one (insignificant) semantic change is switching the order
of emph and strong tags in the output for ***strong and emph***.

We have removed Hard-wrapped_paragraphs_with_list-like_lines tests,
because the new implementation no longer requires a blank line
before a list.