Fix issue #3374

DateTime::ISO8601 doesn't properly handle fractions of a second. This patch fixes that problem.
Workaround for DateTime::ISO8601 deficiency.

Added logic to detect and properly handle ISO8601 date strings that contain fractions of a second.
Fixed incorrect variable name
Added Zend\Stdlib\DateTime object to properly handle ISO8601 formatted dates
Refactored Zend\Stdlib\DateTime::createISO8601Date to Zend\Stdlib\DateTime::createFromISO8601, updated documentation
Fixed annotation of ZendTest\DateTimeTest
Ran php-cs-fixer on Zend\Stdlib\DateTime.php and ZendTest\Stdlib\DateTimeTest.php
Removed file that shouldn't have been there.
Merge commit 'refs/pull/3375/head' of github.com:zendframework/zf2 into hotfix/hotfix/iso8601-factrion-of-seconds
[#3375] Update copyright year
Merge pull request #3375 branch 'hotfix/hotfix/iso8601-factrion-of-seconds'