add @redacted's wonderful xkcd password generator

http://xkcd.com/936/
https://github.com/redacted/XKCD-password-generator
st3: autowrap break on long words, add md standard
st3: 2 space indent for md syntax
use brew bundle and brew cask
st3: sublimelinter-shellcheck

requires shellcheck, which is not in homebrew. must be installed by
cabal, a haskell installer.