Slate: initial config

This is nice; one less thing to configure when switching to another
machine, and it's fast.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Zsh: weaken compinit security checks for the benefit of Homebrew

For security, I run as an unprivileged user, and have a separate admin
account for admin purposes.

Alas, by an unfortunate combination:

  - Homebrew wants to be installed as an admin user
  - Zsh wants to check that the ownership and permission on compinit
    files

This means that Zsh will complain on boot, because the files will be
owned by another user who isn't root. This commit switches off the
security check.

Sigh. It was either that, or run as an admin user, which isn't
desirable either. (Or, dispense with Homebrew...)

So here I am choosing convenience over security, because I've set up too
many machines in my life and I want to streamline the process.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Slate: fix Propane placement in single-monitor layout

Whoops. Was accidentally sticking Propane on the right instead of on the
left.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Zsh: tweak rbenv init for compatibility with Homebrew

Rather than looking for rbenv in $HOME, trust the $PATH to do the right
thing.

This means you can install rbenv in your home directory, or via Homebrew
(in which case it will live in /usr/local) and it will do the right
thing.

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