[REVIEW-3-5] Fix for n#717947, PDF export fixes

[Muthu Subramanian K]

Hi,

http://cgit.freedesktop.org/libreoffice/core/commit/?id=03a651507e34ee423674d2a537f2bb4b509af6d6 
fixes the issue https://bugzilla.novell.com/show_bug.cgi?id=717947

It will be great if someone can review this and cherry-pick it, please?

In brief: When Impress slides with image and notes are exported to pdf 
(along with notes), the images are exported with PreviewSizeHint of 
64x64 and scaled to the original size instead of original image. This 
patch fixes the problem.

Thanks to Thorsten for the initial difficult work on this.

Thanks & Regards,
Muthu Subramanian