Tracks most-used directories to make cd smarter

Current versions:
1.9 HEAD

Homepage: https://github.com/rupa/z

Formula history

Zhiming Wang z: replace `brew --prefix` call with fixed path
Baptiste Fontaine z: bottle unneeded
Satoshi Ohmori z 1.9
Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Joseph C z 1.8
Adam Vandenberg z: remove back-compat caveats
Kaiwen Xu z 1.6.
Adam Vandenberg z: use archive download