Fix false-positive parse of email auto link.
Add `br` to set of block elements.
Nuke all \r from input.

Including but not limited to \r\n -> \n
Allow a block HTML element to follow w/o blank line.

For example "foo\n<table></table>", with just a single newline
beforehand instead of \n\n.

Or even "<i>x</i><table></table>", with no newline beforehand.
Refactor autolink
Require space between name and attributes.

Fixes problem such as parsing <pre> as '(p ([re "re]))
Add $doctype and $xml. Use in $docuement.
Various "pragmatic" HTML parsing changes.
More test cases.
Downgrade performance checks.

As a result of commit e90ee6b parsing test.md is significantly slower.
Separate warn-time and kill-time in random-test

Both warn about parses that takes e.g. > 5 seconds, and also kill the
parse if it takes e.g. > 30 seconds.
Add autolink examples to tokens.