remove v2.2.8 files

git-svn-id: https://plugins.svn.wordpress.org/cf-whiteboard/trunk@854537 b8457f37-d9ea-0310-8a92-e5e31aec5664
v2.2.9 files - new Whiteboard setting, fix PHP warnings, minor bugfix

git-svn-id: https://plugins.svn.wordpress.org/cf-whiteboard/trunk@854538 b8457f37-d9ea-0310-8a92-e5e31aec5664