* MKD_NOSTYLE -- treat `<style>` blocks as regular html.
* some github flavored markdown support; gfm_...() input
methods that put hardbreaks (== two spaces) at the end
of every input line
* a whole bunch of configure.sh tweaks to work around
the tiny detail that clang is even more anal-compulsive
than gcc is.
* support for github flavored markdown backtick-delimited
code blocks (in addition to tilde-delimited codeblocks)
* in the `markdown` program, add
1. -S flag (tell markdown to spit out style sections)
2. -n flag (tell markdown not to output generated text)
1. tables with leading |s
2. \<br> being erroneously treated as a block-level html element
Tweaks for mingw, cygwin, and clang brokeness
Changes contributed by Stefano D'Angelo to clean up the toc html
Correct paragraph blocking to closer match the reference
(text blocks absorb adjacent code lines) and update the
test case error reporter to show the failed input and
the differences between the actual and expected output.