PagePainter:
  Updated drawShape with RasterOperation (Normal, Multiply) for getting
  Highlight annotation types to work. All Highlight annotations are now
  drew using the Multiply raster operation.

Painter_AGG2:
  Replaced the agg_pixfmt_rgba.h pixformat definition template with an
  internal version that implements different raster operations too. The
  new version has been shrinked to the minimum, containing the only code
  needed by kpdf AGG2 rendering engine to work.

Thanks for Rob Buis for telling me the way to go and providing sample code
with his AGG2 algorithms.

svn path=/branches/kpdf_annotations/kdegraphics/kpdf/; revision=405338