Crash with autobrush

[Cyrille Berger]

> If you make a really big autobrush (say, 99.99 -- which would be an ideal
> size for the freehand filter tool), showing the 'general' tab will crash
> Krita because the brush pixmap doesn't fit into the iconbox.
in fact the problem is elsewhere, KisIconWidget::m_item is not affected by 
autobrush and textbrush.

> (Oh, and perhaps the 'fade' parameter should be limited to width/2 and
> height/2 -- otherwise it doesn't fade anymore)
And the algorithm should be modified because when you have a fade of exactly 
width/2 and height/2 it doesn't work. And the square norme should be 
corrected too.
I will take care of it.

-- 
--- Cyrille Berger ---