.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
.osx: Add possible values for AppleShowScrollBars

Ref. #170.
Update shebangs

If the user installs a custom Bash build, why not use it?

Ref. #196 and #198.
README: Add author field
.functions: Add `targz`

`targz some-directory` creates `some-directory.tar.gz`, where compression is handled by either `zopfli` (if available) or `gzip`.
.functions: Avoid `rm` error message in `targz` when `gzip` is used
Merge branch 'master' of https://github.com/mathiasbynens/dotfiles

# By Mathias Bynens (7) and others
# Via Mathias Bynens
* 'master' of https://github.com/mathiasbynens/dotfiles:
  .functions: Avoid `rm` error message in `targz` when `gzip` is used
  .functions: Add `targz`
  README: Add author field
  Update shebangs
  .osx: Add possible values for AppleShowScrollBars
  bootstrap.sh: Pull from the master branch explicitly
  .exports: Always enable colored `grep` output
  .functions: Add `cdf`
  .aliases: Add `week`