Hawk's fork of Dotfriles

My fork of Dotfriles adds the following features:
 + Mac OS X support, including Homebrew for package management
 + SublimeText 2/3 support, including copying config files to the Correct Place on OS X and Linux
 + Ability to install packages from a list in `~/.dotfriles/packages.txt`

Please sanity-check my additions before merging :)
`$OSTYPE` is a global variable provided by `bash`. See http://f00bar.com/blog/2011/07/09/simple-robust-os-detection-in-bash-using-ostype/