Update grep on Mac OSX

Update grep to the latest version using brew on mac!

OSX 10.7 comes installed with grep version 2.5.1 which sadly does not include the –exclude-dir option. To update run the following code

  brew install xz #required for installing grep through homebrew
  brew install https://raw.github.com/Homebrew/homebrew-dupes/master/grep.rb

Enjoy :)