Docs suggestions: (1) Expanded TOC (2) PDF or downloadable HTML

As a new user I’m hitting the Publii documentation pages pretty hard. The
information looks good, but could be made more accessible.  These changes
would help in coming up to speed faster:

1. The TOC on the left with expandable sections is great, but when
   expanding a section the currently expanded section closes.  Better
   to provide an option of having the entire TOC visible, with all sections
   expanded, to ease navigation and back-and-forth reading of sections.
2. There is a lot to absorb, a process that would be easier if there was a
   way (e.g. a PDF or HTML version) that could be printed for offline
   reading.