Add real time search/filter

[stacyk]

In addition to the whole site search #28 it would be nice to have a filter like feature like on Lonely Planet's Style guide: http://rizzo.lonelyplanet.com/styleguide/design-elements/interface-icons

Would be useful for some components like icons and maybe colors.

[jgerigmeyer]

JS for reference: https://github.com/lonelyplanet/rizzo/blob/5ba4f99bd91ad2e3f8810ac6308915520d358cbe/app/assets/javascripts/lib/styleguide/svg.js

I think before this gets further we need a design proposal. Where all does the search show up (icons? colors? fonts? where else?), how should it work, etc.