[#2006] package_dictize should not have to dig into revisions unless you ask for an old version. Add new_tests. In the process we lose the "revision_timestamp" property when you package_show, resource_show etc, but that is not particularly useful info as the package revision stays the same if you edit its extras or tags, for example. And we lose the revision_id on resources too - revisions are out of favour anyway. When displaying old version of the dataset, the date was wrong - it was package_revision date, ignoring extra changes - this is now fixed.