Add zsh keybindings
Change prompt construction

 - hidden directories now appear as two characters: '~/.dotfiles/zsh/
   config' appears as '~/.d/z/config'

 - path manipulation uses sed instead of shell string
   manipulation
Add zsh colors settings
Fix prompt for named directories
Merge branch 'master' of https://github.com/ryanq/dotfiles
Merge branch 'master' of https://github.com/ryanq/dotfiles