• Open files in binary mode (#113, Nick Wellnhofer). Now that cmark
  supports different line endings, files must be openend in binary mode
  on Windows.
• Reset partially_consumed_tab on every new line (#114, Nick Wellnhofer).
• Handle buffer split across a CRLF line ending (#117). Adds an internal
  field to the parser struct to keep track of last_buffer_ended_with_cr.
  Added test.