.aliases: Add `week`

Thanks to @sindresorhus: https://twitter.com/sindresorhus/status/312206490880589824
.functions: Add `cdf`

`cdf` changes the working directory to the top-most Finder window location. Thanks to @sindresorhus and @paulirish!
.exports: Always enable colored `grep` output
bootstrap.sh: Pull from the master branch explicitly
Merge branch 'master' of github.com:mathiasbynens/dotfiles

* 'master' of github.com:mathiasbynens/dotfiles:
  bootstrap.sh: Pull from the master branch explicitly
  .exports: Always enable colored `grep` output
  .functions: Add `cdf`
  .aliases: Add `week`