Crash while testing brush settings

[Lukast dev]

> Actually it counts as a KisImage. Since this is the case, what can I do to
> make the brush work in the settings widget?

I solved this problem in one of my brush engines like this:

I needed to know the dimension of the image (widht/height) from KisImage.
So I decided that if there is KisImage present, I will use KisImage dimension,
otherwise I use some dummy dimension like 1000x1000 or something like that :)

Cheers
LukasT