DBus signal - imageSaved

REVIEW:130021

I would like to propose one more signal - imageSaved(strFilename) which is emitted just after data is written to disk or uploaded. That might happen not simultaniously with scanComplete() and also conviniently communicates filename.

Usecase is following: my HP has some bug (or probably this is a driver bug) and for color mode its scans are quite reddish. And It can't be fixed with gamma options provided by HP driver. I found out that I can get better results if postprocess files with GIMP. It allows adjust color balance of shadows/midtones/highlights pixels separately. I've written a script for that.
With help of the new signal user can automatically execute some prostprocessing scripts like that.

Example script demonstrates this gimp trick.
New signal could be also used to automatically send file to printer and then to remove it.