[Tracker] Updated shared metadata specification

[Jamie McCracken <jamiemcc blueyonder co uk>]

Hi Ross,

I have updated the metadata spec at

http://freedesktop.org/wiki/Standards/shared-filemetadata-spec

Please review and let me know if you think anything is missing.

I have added a data type section and made it clear that all datetime 
types are in ISO 8601 format.

WRT Exif, I have tried to leave out the useless metadata (IE a lot of 
EXIF metadata is highly technical and is solely for the benefit of 
printing machines and image processing software and not necessarily 
useful as human readable/searchable metadata). I have included 
"Image.FocalLength" so you could search for pictures taken with wide 
angle lenses. BY all means let me know if it needs more.


--
Mr Jamie McCracken
http://jamiemcc.livejournal.com/