Journal and database testing. - Add to Import/Export test to also test that journals are correctly retrieved - Fix a bug in anydbm backend that didn't export journal 'set' actions where the previous value was None -- all other backends export them correctly so I consider this a bug of anydbm - Fix journal import/export of Date and Interval for metakit - Fix journal import of Password for metakit - Fix setting of Password oldvalue for metakit -- this would be written as the string "None" instead of the value None. Note that existing databases *will* have wrong log-entries. Since this is only for passwords -- and old passwords aren't of much importance -- I consider this fix to be enough... This fix makes the Journal import/export test run for metakit.