Fix QDirectFBPixmapData::fromImage
Fix QDirectFBPixmapData::fromImage

This fix should optimize pixmap loading on most platforms and also fixes
a bug on a certain hardware where the alpha channel of an image was not
retained upon loading it.

This patch also takes care of handling dithering better in
QDirectFBPixmapData::fromImage().

Reviewed-by: Donald Carr <38431beafb109b90c28ed5e81bc7ca041dd4c8fb@nokia.com>

pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,radekp/qt,radekp/qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt