CONTRIB-4144 Bump to 2013021400 (v2.2.5)

Changes:
- CONTRIB-4151: added moodle phpunit support (via local_codechecker_testcase).
- CONTRIB-4149: added phpcompatibility sniffs (git://github.com/wimg/PHPCompatibility.git).
- CONTRIB-4145: upgrade to PHPCS 1.4.4.
- CONTRIB-4144: add (this) CHANGES.txt file.