Add z-scroll and Z-commands
Remove release.nix

I keep my own copy.
Remove outdated/redundant stuff from doc

We link to most of this (already compiled) stuff at the bottom of
README. I leave the blog directory intact for now because because we
should port the contents of some of the posts first.
Some cleanup
Merge pull request #592 from siddhanathan/master

Add z-scroll and Z-commands