- old_theme is the old SSI-based theme (no clue where from, some copy-paste
  action back in 2009)
- new_theme is based on https://github.com/Vimux/Mainroad.git
- overlay in query: https://github.com/gasparesganga/jquery-loading-overlay/releases/tag/v1.5.3
- http://saimiri.io/2016/06/comments-in-hugo/ for comments