parse a time-zone offset component

History

Time	Change
2014-05-06 08:38:41+00:00	Created
2014-05-06 08:38:41+00:00	Associated with 8458
2014-05-06 12:44:34+00:00	Disassociated from 8458
2014-05-06 12:44:53+00:00	Associated with 21801