been fixed. If someone finds one of those, please tell me.
Here are thread generator pros/cons:
- generation is ~20% slower
+ thumbnaillist or pageview scrolling is fast (never blocked anymore)
+ all UI feels so better and responsive
So:
o thumbnaillist will be all ASYNC.
o pageview will use ASYNC for _preloading_ next pages and a mixed A/S for
  scrolling/viewing the document
p previewwidget and others (searches, etc) are SYNC as obvious.
Btw now async generation is enabled everywhere.

svn path=/branches/kpdf_experiments/kdegraphics/kpdf/; revision=373810