Wrap at 72 characters for git commit messages

The body of a git commit message is conventionally ([1], [2]) wrapped at
72 characters. This commit adjusts .vimrc to automatically wrap the body
of git commit messages at 72 characters.

[1]: http://robots.thoughtbot.com/5-useful-tips-for-a-better-commit-message
[2]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
Add /usr/local/sbin to PATH

Some homebrew formulae, (e.g. [RabbitMQ][1]) link binaries here.

[1]: https://github.com/Homebrew/homebrew/blob/master/Library/Formula/rabbitmq.rb
include, filter, user
Revert "include, filter, user"

This reverts commit 383612ac4cb05641fce1a9b1051afd238365f69e.
Spell check git commits
Use POSIX compliant test command in git hooks

Ubuntu systems will error out on `[[` in shell scripts with `#!/bin/sh`
as the shebang.
Merge remote-tracking branch 'upstream/master'