Added ROI filtering option; did some renaming
Fixed bug: Unselecting all filter options didn't refresh view
Added 'Has ROIs' and 'No ROIs' options to quick search drop down
Bugfix: Quicksearch drop down
Filtering via Quicksearch drop down was not correctly reflected by the FilterDialog
Replaced filter icon
Updated copyright date
Implemented Mark's suggestions

Fixed missing break; use CollectionUtils; completed if statement with else
Removed the superfluous showAll flag again
Fixed some sync issues between quicksearch drop down and filter dialog
Bugfix: Building the intersection of filter results didn't work
Fixed comment
Fixed another problem with quicksearch - filterdialog sync
Implemented Mark's suggestions

Corrected indention and comment; changed to iterate over values
instead of keys and calling .getValue()
Added text "ROIs" to filter toolbar label
Merge pull request #2171 from dominikl/filter_by_roi

Added ROI filtering option