[pdf] Add support for PDF/X and additional xmp metadata
Recognise if pdf is PDF/A or PDF/X and additionally extract the following metadata from the embedded xmp file: Author, Creator, Producer, Keywords, Subject, Title and creation/modification dates.
Using the sample pdf from LaTeX package pdfx (sample.pdf) you get the following file properties dialog when the current version of evince is used.
In contrast, using evince from xmp-metadata branch you get:
To my knowledge, this merge request deals with the following issues: #771 (closed), #93 (closed), #626