Enable mercurial information in prompt
Use vim input mode in ZSH

This is, of course, a work in progress. I'm not happy with the key
bindings yet, but my intention is to add or fix them when I encounter
problems rather than trying to do everything up front.

I have copied some bindings I found earlier though, but that's just to
have something to read to understand how one does bindings in the first
place.
ZSH: Use vim bindings instead of vi bindings to delete characters
Try the SearchHighlighting vim plugin
Improve irb methods with a matcher to grep methods on one go
Disable flow control in ZSH
Big change to how PATH is built

This is still me trying to work around Apple fucking with PATH all the
time on macs. The Linux distros are usually more respectful of user
settings.