[noise] Cosmetic changes to website/wiki

[Trevor Perrin]

Made a few improvements to website and wiki:

Website
 * Added "Adopters" section

Wiki
 * Added "Historical" section for old spec
 * Mentioned Anup's Python library
 * Removed SSK from "Library Feature Matrix"
 * Added "(old)" to Benchmarks / Library Feature Matrix
   (would be great if someone wanted to update these sections for more
   libraries)

Spec
 * Didn't change revision, but slipped in some typographical tweaks:
 * Better table spacing in HTML
 * Better page breaks in PDF
 * Superscripts instead of carets for 2^64 etc.

Sorry I haven't had time for more substantial work last couple of
months.  Q1 next year I'll have more time to push on some new features
and implementations (e.g. postquantum, more patterns, etc).

Trevor