Bugfix #8: Categegories display counts and support for loading indicator

The categories of the global search now display the icon of each category and
also the counts/totalcounts. Furthermore a loading indicator is displayed when
the query takes longer.
The category title is a link that opens the corresponding list views with the search
term as a query URL parameter.
Bugfix #8: Various list views now read out query string from URL

All lists that support searching now put the searchString into the URL as a query
parameter. This allows to link to a specific searchString from the global searchbox.
Enhancement: List-View for publications support searching

It's now possible to search through the list of publications.
Merge branch 'global_search'