Merge lp://qastaging/~soliloque/simple-scan/remove_ps_tiff into lp://qastaging/~simple-scan-team/simple-scan/trunk

Remove code for ps and tiff support

The file chooser dialog offers three format for saving files: PNG, JPEG, and PDF. I consider this is the right thing to do as it covers pretty much every use cases: PDF for having all images in a single file, JPEG for having compact files at the price of using lossy compression, and PNG for retaining all scanned pixels, maybe for further editing with another software.

Double-clicking a page in simple-scan will open it with an image viewer. However, this feature wasn't following what the file chooser dialog does as it saves the image in the TIFF format. For this feature to be in line with the file chooser dialog, I changed the image format used from TIFF to PNG. TIFF offers nothing over PNG for what Simple-Scan does anyway and PNG is more widely supported than TIFF at this time. This make the code for supporting TIFF file format useless.

There is also code for supporting PostScript file format. This format doesn't offer anything over PDF -- PDF is in fact better as it supports icc profiles. Furthermore, PDF is vastly more widely supported than PDF. As simple-scan doesn't use or offer to save in PostScript, this code isn't useful too.

So, to summarize, this merge would remove the code -- and the need to maintain that code -- supporting PostScript and TIFF file formats without removing any feature or usefulness to Simple-Scan.