GWT: x.x, Edition, Allow multiple facets when browsing by motive

Currently, a click on “Search”, “Next” or “Previous” closes all facets except “courante” in GRAAL.
Opening other facets causes loss of highlighting.

(from redmine: issue id 613, created on 2014/02/15 by Alexey Lavrentev)

added type::task + 1 deleted label

changed milestone to %Portal 0.7

added time estimate of 5h

added ui label