The previous test condition would cause errors because even though brew didn't
exist, the directory /share/zsh/site-functions did and it would throw error
messages on non-homebrew systems.
--stat added, jumpstat alias removed.
Options passed to the `j` function will now be passed on autojump. As a result,
directories beginning with `-` are no longer supported.
A -s short alias for --stat is added. Instead of using jumpstat, use `j --stat`
or `j -s` instead.
As best I can tell, ZSH introduced the "=~" condition somewhere around 4.3.5 or
4.3.9. In either case, autojump will use =~ for versions higher than 4.3.5 and
-pcre-match for older versions of ZSH.
