fixed license missing on experimental file and added a test rule for David F. Skoll from Mailing list

git-svn-id: https://svn.apache.org/repos/asf/spamassassin/trunk@1513679 13f79535-47bb-0310-9956-ffa450edef68
fixed license missing on experimental file and added a test rule for David F. Skoll from Mailing list

git-svn-id: https://svn.apache.org/repos/asf/spamassassin/trunk@1513680 13f79535-47bb-0310-9956-ffa450edef68