Fix scroll bug on mobile and PDF print

[kiwi0fruit]

• Fix scroll bug,
• Experiment with self-hosting all Gitbook legacy toolchain.
• Check Link to asset files navigated directly GitbookIO/theme-default#62 and Reenable local file navigation GitbookIO/theme-default#57
• May be replace scroll to jumps
• If

  .book-body {
     overflow-y: visible;
  }
  

  then sepia and night get side white stripes.

[kiwi0fruit]

Dropped in favor of kiwi0fruit/misc#1