chore(bower): add kraken-css-12 to dependencies
layout(ribbons): add ribbons to the CSS

Any block object can now be decorated with a CSS ribbon, after being
enclosed in DIVs like this:

      <div class="img-wrapper">
        <div class="ribbon-wrapper">
          <div class="ribbon favorite"></div>
        </div>
        <!-- IMG that needs to be 'ribbonized' -->
        <img ng-src="{{pl.img}}" alt="hotel image">
      </div>