ZF-2338: Exif data not parsed from photo entries


Exif data is not currently being parsed from photo entries because: a) the namespace for Exif is not defined in Zend_Gdata_Photos b) Exif/Extension/Tags was broken, not passing the dom element when creating children

There are also missing tests for the Exif classes. This fixes some, but more needed to be added.


Code written by mjoshi and rboyd. Needs reviewed.