Implement the possibility to switch off all assigned object-effects and
slide-transitions in Impress quickly at once.

Background: Currently one needs to select each object and deselect the assigned
effect, same with each slide, means a lot of steps within a presentation to get
rid of assigned effects and slide transitions. And often a presentation has a
high amount of pages.  

Scenarios: At reviewing a presentation assigned effects and slide transitions
can be disturbing and hold up the work. So for this kind of work a temporary
switch-off is useful. The second scenario is, to take over a presentation from
someone else and to adjust for own needs; therefore it might be useful to be
able to remove those effects and not only to disable them. 

Spec is in work.