Try to fail more gracefully on core data failures

When migrations fail, just act as a new app.

That shouldn't really happen for new releases, but it gets annoying when
switching between different development branches

git-svn-id: http://ios.svn.wordpress.org/trunk@3769 7d847f7c-ffe1-4a24-85be-b788d016d96a
Updated pods

git-svn-id: http://ios.svn.wordpress.org/trunk@3770 7d847f7c-ffe1-4a24-85be-b788d016d96a