[evince] PDF xmp metadata support (patch)

["Rigas, Evangelos" <e rigas cranfield ac uk>]

Hi all,

I have added support for xmp metadata tags.
The xmp tags supported are creator (author), subject (keywords),
creation/modification dates, title, description (subject).
Also, it recognises if the pdf is PDF/x.

If the xpm metadata exist, the will overwrite the ones from the info
dictionary of the pdf.

I will like to ask if someone can guide me to submitting the patch.

This patch will solve at least the following bugs:
755984, 585557, 781562


Thanks,

Evangelos Rigas