Here is the first test on rendering filter effects. It applies constant
gaussian blur to every rendered object of type NRArenaShape. This is
mostly to test the speed of rendering filter effects in real time.
This test does not apply blurring to all types of objects - that would
result in blurring the object, blurring the layer the (already
blurred) object is on, etc.
The biggest problem at the moment seems to be transparent areas
appearing, when an object is drawn in several smaller pieces rather than
in one piece. Guess the object needs to be drawn on a larger buffer thet
is larger than the result will be - thus allowing blurring to take in to
account the pixels outside the actual area, we are rendering to.