.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
.vimrc: Explicitly use the Molokai theme
Brewfile: install `moreutils`, if only for `sponge`

Hat tip: @chastell / http://talks.chastell.net/kodio-2014/#/21
Brewfile: install `pv` (pipe viewer)

Hat tip: @chastell / http://talks.chastell.net/kodio-2014/#/39
.osx: Make Dock more transparent

Closes #346.
Brewfile: explicitly list non-default taps
Merge branch 'master' of github.com:mathiasbynens/dotfiles

* 'master' of github.com:mathiasbynens/dotfiles:
  Brewfile: explicitly list non-default taps
  .osx: Make Dock more transparent
  Brewfile: install `pv` (pipe viewer)
  Brewfile: install `moreutils`, if only for `sponge`
  .vimrc: Explicitly use the Molokai theme
  Brewfile: Install ImageMagick with WebP support
  .osx: Kill `cfprefsd` after changing preferences