A new config variable 'date_format' is introduced in _config.yml.
It can either be set to "ordinal" to use the current format or it
can be given a string complying to strftime() format identifiers.
- Added ARIA setting `aria-live="polite"` to comment output
- Removed duplicate <div id="disqus_thread"> from page/post templates
- Moved blocking JavaScript loading to the end of the document body.
- Merged JavaScript code for index and pages/posts using conditionals
- Moved global JavaScript disqus variables into the anonymous function to stop pollution of global namespace