[wp-xmlrpc] WP 2.2.1 breaks Ruby 1.8.2

[Joe Cheng]

> A compromise solution that would muddy the XML namespace but would
> at least allow for all parties to "win" would be to add a separate
> XML attribute for clients who want the GMT time explicitly.

Or how about a separate member that says what time zone is being
used? This way there's no data duplication.

<member>
  <name>dateCreated</name>
  <value>
    <dateTime.iso8601>20070623T01:22:18</dateTime.iso8601>
  </value>
</member>
<member>
  <name>dateCreatedTimeZone</name>
  <value>+08:00</value>
</member>