Update the website.

Forget the massive overhaul at this point. Let's just update the links and the text. Example: get rid of the Florincoin reference on the Documentation page. Bury the tZERO references since they are no longer using FLO (or at least suspended their use). Update the exchanges to include Abra, etc. Eliminate references to things that happened in 2019 and update it with things that happened in 2020.