patterns: add media object styles and markup
media styles: convert spaces to tabs
gemfile: add autoprefixer-rails, remove redundant modular-scale gem
add autoprefixer to config.rb, remove all vender prefixes with the exclustion of some -webkit- specific ones
Merge branch 'feature--media-object' of github.com:getchopstick/chopstick-boilerplate

* 'feature--media-object' of github.com:getchopstick/chopstick-boilerplate:
  media styles: convert spaces to tabs
  patterns: add media object styles and markup