Vim: add emmet-vim plug-in

For a few years, almost every time I edit markup, I'm actually editing
Haml. In the near future I expect to be editing more HTML directly, so
this plug-in (an unofficial Vim implementation of the upstream Emmet,
previously known as Zen Coding).

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Vim: add a jsx snippets file

Not much in it yet, but it's a start.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Vim: use ftdetect to detect JSX files

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Git: add back old user.name and user.email config

In commit afc9af3e90182b3596edb9a9ec I pulled this out, requiring me to
set it up on a per-project basis rather than risk committing using the
wrong address.

I don't think I've committed using the wrong address since forever, due
to compulsive use of `git show` to review commits before pushing, so I
think I can make this the default again.

Additionally, since commit f445fb721ed64d1b0f5b27d2 I've been able to
add per-machine overrides, so it makes sense for me to use
win@wincent.com on my personal machine and a work override on my work
machine.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
*sh: remove `z` alias

Zeus has proven to be fairly flaky, and with Rails 4.1 come Spring, so
time to give it the flick.

Signed-off-by: Wincent Colaiuta <win@wincent.com>