2.0.0.alpha3

CHANGES:

• Expose the HTML escape function htmlentities (#295 @cuihtlauac)

• Support generation of identifiers in headers (#294, @tatchi)

• Support GitHub-Flavoured Markdown tables (#292, @bobatkey)

• Update parser to support CommonMark Spec 0.30 (#266, @SquidDev)

• Preserve the order of input files in the HTML output to stdout (#258,
  @patricoferris)

• Fix all deviations from CommonMark Spec 0.30 (#284, #283, #278, #277, #269,
  @tatchi)