Brewfile: Install `p7zip` (i.e. `7z` etc.)
Merge branch 'master' of git://github.com/mathiasbynens/dotfiles

* 'master' of git://github.com/mathiasbynens/dotfiles:
  Brewfile: Install `p7zip` (i.e. `7z` etc.)
.osx: Kill `cfprefsd` after changing preferences

As of OS X 10.9 this is necessary to make sure the changes persist.

Closes #330.
Brewfile: Install ImageMagick with WebP support
Merge branch 'master' of git://github.com/mathiasbynens/dotfiles

* 'master' of git://github.com/mathiasbynens/dotfiles:
  Brewfile: Install ImageMagick with WebP support
  .osx: Kill `cfprefsd` after changing preferences