Pushed a new version to correct notes problem

* Continuing on in the grand tradition of rapid point releases, this is
  a minor, yet important, errata fix. Current versions of RedCarpet did
  not work with both instructor notes and `:strikethrough` enabled. This
  release turns `:strikethrough` back off and a future update will rework
  the syntax for instructor notes.
* Enables static supplemental material generation
* Output cleaner HTML
* Allows running without a `showoff.json` config file again.