preempt pull request into Redcarpet from https://github.com/vmg/sundown/pull/141
expose :footnotes extension in Ruby
Ruby hooks for footnotes generated HTML
register footnote hooks in Sundown, too
haste = waste
SPAN_CALLBACK
concise README, and less tomfoolery
Merge \r\n fix from 511d6e973eefafb98f3a78cf831e53111ac81667 + memory leak fix from 9bf0176339b4a0823efb159b4a01fc57d7afb1a9
Merge remote-tracking branch 'patch/master'

* patch/master:
  Merge \r\n fix from 511d6e973eefafb98f3a78cf831e53111ac81667 + memory leak fix from 9bf0176339b4a0823efb159b4a01fc57d7afb1a9
  concise README, and less tomfoolery
  SPAN_CALLBACK
  haste = waste
  register footnote hooks in Sundown, too
  Ruby hooks for footnotes generated HTML
  expose :footnotes extension in Ruby
  preempt pull request into Redcarpet from https://github.com/vmg/sundown/pull/141

Conflicts:
	README.markdown
	ext/redcarpet/markdown.h