Fix update multiple metadata
Add rspec helper for running feature tests

with personas db, various browsers, etc ...
Feature test for batch editing metadata
prepare routes and tab-navigation
import raw html from styleguide for mockup
more structuring: controller method, partials
more structuring: tab navigation, partials also for media_sets
throw out static mockup, build with haml and data. cleanup unused templates.
#tmp: directly edit style guide. add data-properties for scripting.
js: implement filterbar functionality (in style guide) #tmp
js: implement slider functionality (in style guide) #tmp