upgrade to v3.1.1 (from upstream)

Long overdue upgrade from version 3.0.0-beta to 3.1.1!

TODO:
1. [done] still need to add manta glyphs section
2. [done] bootstrap glyphs section doesn't seem to render in docs
3. [done] verify that the new h* variables are set right (used to be computed)

@Delightend