Links to NXT repos

Hey all,

Last meeting Dzmitry asked which repos where the upstream for NXT,
Chromium's WebGPU prototype. Here they are:

   - https://github.com/google/nxt-standalone is the standalone library
   implementing the prototype outside of browsers.
   - https://github.com/kangz/nxt-chromium is a fork of Chromium
   integrating this library. I'm in the process of updating it to ToT Chromium
   and ToT NXT.

Cheers,

Corentin