Fix for issue #20358: clear object cache to avoid using all server memory while running checktargets.php
Update copyright year to 2013
Remove classes which were added by error in commit 7a73f8439fa1f2e7b279a226cade78c2cc36f159 (15/3/2012)
More cleanups of phpdoc headers
Update version numbers and changelog info
Add more backup file extensions to gitignore list