• Implement spec changes for list items:
  • Empty list items cannot interrupt paragraphs.
  • Ordered lists cannot interrupt paragraphs unless
    they start with 1.
  • Removed "two blank lines break out of a list" feature.
• Fix sourcepos for blockquotes (#142).
• Fix sourcepos for atx headers (#141).
• Fix ATX headers and thematic breaks to allow tabs as well as spaces.
• Fix chunk_set_cstr with suffix of current string (#139,
  Nick Wellnhofer). It's possible that cmark_chunk_set_cstr is called
  with a substring (suffix) of the current string. Delay freeing of the
  chunk content to handle this case correctly.
• Export targets on installation (Jonathan Müller).
  This allows using them in other cmake projects.
• Fix cmake warning about CMP0048 (Jonathan Müller).
• commonmark renderer: Ensure we don't have a blank line
  before a code block when it's the first thing in a list
  item.
• Change parsing of strong/emph in response to spec changes.
  process_emphasis now gets better results in corner cases.
  The change is this: when considering matches between an interior
  delimiter run (one that can open and can close) and another delimiter
  run, we require that the sum of the lengths of the two delimiter
  runs mod 3 is not 0.
• Ported Robin Stocker's changes to link parsing in commonmark/commonmark-spec#101.
  This uses a separate stack for brackets, instead of putting them on the
  delimiter stack. This avoids the need for looking through the delimiter
  stack for the next bracket.
• cmark_reference_lookup: Return NULL if reference is null string.
• Fix character type detection in commonmark.c (Nick Wellnhofer).
  Fixes test failures on Windows and undefined behavior.
  • Implement cmark_isalpha.
  • Check for ASCII character before implicit cast to char.
  • Use internal ctype functions in commonmark.c.
• Better documentation of memory-freeing responsibilities.
  in cmark.h and its man page (#124).
• Use library functions to insert nodes in emphasis/link processing.
  Previously we did this manually, which introduces many
  places where errors can creep in.
• Correctly handle list marker followed only by spaces.
  Previously when a list marker was followed only by spaces,
  cmark expected the following content to be indented by
  the same number of spaces. But in this case we should
  treat the line just like a blank line and set list padding
  accordingly.
• Fixed a number of issues relating to line wrapping.
  • Extend CMARK_OPT_NOBREAKS to all renderers and add --nobreaks.
  • Do not autowrap, regardless of width parameter, if
    CMARK_OPT_NOBREAKS is set.
  • Fixed CMARK_OPT_HARDBREAKS for LaTeX and man renderers.
  • Ensure that no auto-wrapping occurs if
    CMARK_OPT_NOBREAKS is enabled, or if output is CommonMark and
    CMARK_OPT_HARDBREAKS is enabled.
• Set stdin to binary mode on Windows (Nick Wellnhofer, #113).
  This fixes EOLs when reading from stdin.
• Add library option to render softbreaks as spaces (Pavlo
  Kapyshin). Note that the NOBREAKS option is HTML-only
• renderer: no_linebreaks instead of no_wrap.
  We generally want this option to prohibit any breaking
  in things like headers (not just wraps, but softbreaks).
• Coerce realurllen to int. This is an alternate solution for pull
  request #132, which introduced a new warning on the comparison
  (Benedict Cohen).
• Remove unused variable link_text (Mathiew Duponchelle).
• Improved safety checks in buffer (Vicent Marti).
• Add new interface allowing specification of custom memory allocator
  for nodes (Vicent Marti). Added cmark_node_new_with_mem,
  cmark_parser_new_with_mem, cmark_mem to API.
• Reduce storage size for nodes by using bit flags instead of
  separate booleans (Vicent Marti).
• config: Add SSIZE_T compat for Win32 (Vicent Marti).
• cmake: Global handler for OOM situations (Vicent Marti).
• Add tests for memory exhaustion (Vicent Marti).
• Document in man page and public header that one should use the same
  memory allocator for every node in a tree.
• Fix ctypes in Python FFI calls (Nick Wellnhofer). This didn't cause
  problems so far because all types are 32-bit on 32-bit systems and
  arguments are passed in registers on x86-64. The wrong types could cause
  crashes on other platforms, though.
• Remove spurious failures in roundtrip tests. In the commonmark writer we
  separate lists, and lists and indented code, using a dummy HTML comment.
  So in evaluating the round-trip tests, we now strip out
  these comments. We also normalize HTML to avoid issues
  having to do with line breaks.
• Add 2016 to copyright (Kevin Burke).
• Added to_commonmark in test/cmark.py (for round-trip tests).
• spec_test.py - parameterize do_test with converter.
• spec_tests.py: exit code is now sum of failures and errors.
  This ensures that a failing exit code will be given when
  there are errors, not just with failures.
• Fixed round trip tests. Previously they actually ran
  cmark instead of the round-trip version, since there was a bug in
  setting the ROUNDTRIP variable (#131).
• Added new roundtrip_tests.py. This replaces the old use of simple shell
  scripts. It is much faster, and more flexible. (We will be able
  to do custom normalization and skip certain tests.)
• Fix tests under MinGW (Nick Wellnhofer).
• Fix leak in api_test (Mathieu Duponchelle).
• Makefile: have leakcheck stop on first error instead of going through
  all the formats and options and probably getting the same output.
• Add regression tests (Nick Wellnhofer).