add numerous html5 formatter tags
dirty formatter hack for no link spanning
fix poplink with new sub routine
consolidate link and poplink sub routines
clean up another anchor nesting edge case
add line breaks to formatting output
fix tests to suit new formatter output

[FIXME] known failure of test 64 "link" (over paras)
add simple link and poplink format tests
fix nesting for links spanning paragraphs

FIXME: Too greedy.  Incorrectly catches single paragraphs.
add new test and updated more test output
seems correct except for some whitespace differences
add link wrapping block test
whitespace fixes
add poplink wrapping block test
add link test over complex nested blocks
add test block over a list
fix the poplink over blocks test
allow poplink to work over blocks
don't consume [] for list items

they should contain only character markup, which should be consumed
before we get to this point.

Previously we'd consume the final ] from a surrounding block and produce
bad markup
add newlines around hr tags