Update CONTRIBUTING.md

Add a cheat sheet for compiling with nix... most other docs out there on the web have some strange ways getting/compiling/using node.js

Minimum dev environment change for node.js version to match current production
Update CONTRIBUTING.md

Missed global flag
Update CONTRIBUTING.md

Add some more see also refs applicable
Update CONTRIBUTING.md

Typo
Update Terms-of-Service.md

Expand a little more on libraries
Update Terms-of-Service.md

Some clean up with legalese
Update CONTRIBUTING.md

Syntax highlight a few things