Fill_painter broken and colordistance in autolayer

[Bart Coppens]

I've been playing a bit with the fill painter and the autolayers, and I think 
I've found a problem. The coding itself didn't cause real problems, but I 
can't get it to fill the right area. For some strange reason, it fills the 
entire image instead of filling the selection that is constructed.

This could be caused by an error I made, but I suspect there's something wrong 
with the KisSelection I use. I already tried writing KisPaintDevice::pixel 
and setPixel so that they uses an iterator (they're used by the selected 
parts of a KisSelection), but that didn't seem to work.

Should I commit the changes I made so that you can have a look?

Bart Coppens