fixed issue 23 : ANDing two policies was confused by allowWithoutAttributes...

fixed issue 23 : ANDing two policies was confused by allowWithoutAttributes overrides of elements like <img>,<a>,<span> that are by-default dropped without elements

git-svn-id: http://owasp-java-html-sanitizer.googlecode.com/svn/trunk@220 ad8eed46-c659-4a31-e19d-951d88f54425