FilterChain: add and use count() function
FilterOr: override operator change for NOT

Replacing an OR filter with a NOT operator should return a NOT OR
when the OR contains more than one entry
Widget\Tabs: use icon for dropdown tabs
Web\Request: the request should know the URL
show/contact: sort notifications
components/selectioninfo: use help icon for help
servicesummary: show ok count only when available
FilterEditor: add failsafe string cast
FilterEditor: add getter and setter for Filter

We will shift quite some logic over here
FilterEditor: url-setter and protected lazy-shortcut
FilterEditor: allow to set the query from outside

Query will be used to provide a column list
FilterEditor: allow additional parameter control

We may want to keep additional parameters in our url and ignore other
ones when the filter changes
FilterEditor: make constructor parameter optional

...and use new setters
FilterEditor: add compact search render support

We show the search box and a filter preview while not modifying the
filter
FilterEditor: add redirect support

Not the cleanest way, could be improved
FilterEditor: no title, add cancel button
FilterEditor: addTo method for special operations

Removed obsolete mark function
FilterEditor: do not export removal function
FilterEditor: readability
FilterEditor: add a couple of link generators

remove/add/strip/cancel