pdftopdf: assume print-scaling=auto by default. Fixes #237

[ValdikSS]

cups-filters 1.x rotate already-landscape documents according to printer paper path, and libcupsfilters 2.1.x do the same at least since V2.0rc1, where print-scaling=auto was used as default.

Use print-scaling=auto as default for PDFio pdftopdf as well.

[ValdikSS]

@uddhavphatak please check if this is appropriate. Works for me.

[uddhavphatak]

@ValdikSS just checked it, this works! I had set the tag as NONE by default, as I was not aware of the functionality of this filter. Thanks for debugging and solving the issue!

[alerque]

This is not a good assumption, and I can't seem to override it. When using a rotation, the print scaling seems to be getting set to auto now, and ever -o print-scaling=none seems to have no effect when rotating pages. I already had to work around the media box rotation settings not being honored by manually setting the output rotation, but now I can't get rid of the scaling at all!

I have had to downgrade to libcupsfilters 2.1.x because the 2.2.x releases seem to be an unmitigated disaster. Proper PDF handling does not seem to have been considered at all and all my production print jobs are scrambled and there seem to be no combination of options to fix them.

[ValdikSS]

Make a new issue with its description.