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 :)
Your brew and apt scripts are not downloaded externally. This was originally on purpose, so that with an old version of the first file you could grab updates. (that's why there's a with-sudo companion script.) I do appreciate the check for an existing file though, that's a good idea.