indicates if only the defined counter should be deleted, implemented new
flag in file state machine and sql state machine, introduced
Sql->returnNullified() to nullify false keys and Sql->getSQLOp() to have
the operator determination at one place, added logging to the file->db
migration script, changed ZPushAdmin->RemoveDevice() to use the new
flag, Utils::PrintAsString() understands "null" now.

Released under the Affero GNU General Public License (AGPL) version 3.