ajaxified category sidebar
letzte ebene im category sidebar kein link mehr
category sidebar now works with filters, ajaxified, needs refactoring
search takes values given by dropdowns and cateory sidebar
fix #821 - add canonical-rails gem. check canonical urls from time to time!
Merge branch 'feature-5-grid' of github.com:fairnopoly/fairnopoly into feature-5-grid
Merge branch 'feature-5-grid' into feature-exhibraries

Conflicts:
	config/application.rb
add stock-up and book specific placeholders