Add w3c date mask, use different method for atom date parsing

Description

Added new date mask to handle explicit time zones (e.g. -02:00). Changed the
DateParser method in the Atom10Parser for entry updated and published date so
custom date masks can be handled.

Environment

None

Status

Assignee

ROME Jira Lead

Reporter

jashaj

Labels

None

Participants

None

Fix versions

Affects versions

current

Priority

Major