Printed timezone, full ISO 8601, with timestamps.

The current date format, "2013-12-05 10:08:30", does not include the
timezone and can be confusing when the timezone is different than
expected. Add the timezone and the letter "T" between the date and time
to match the ISO 8601 standard.

"2013-12-05 10:08:30" -> "2013-12-05T10:08:30-0800"

Review: http://reviews.apache.org/r/16096