Query monthly token databases.
Because couchdb won't automatically purge deleted files, the tokens database may increase indefinitelly. Because of that, the tokens database will be replaced by a monthly token database with name @tokens_NNN@ where NNN is the number of months since the epoch.
We have to adapt soledad so it queries these new token databases to grant access to users.
(from redmine: created on 2015-03-09, closed on 2015-03-19)