filter preview dialog

[Cyrille Berger]

> Oh -- a remark: I'd prefer if there were as few abstract methods as
> possible. Wherever we can choose a sensible default, let's have the base
> class return the default, making life easy for the subclasses. In this
> case, I propose to let KisFilter::supportsPreview return false by default.

It might be also true for supportsPainting ? And I was wondering if it might 
good idea to have such information stored into an xml file.

-- 
--- Cyrille Berger ---