Backport (7.9) - Html cleaner removes tags and attributes added by the default CKEditor plugins

Following tags can be inserted with the default options Hippo delivers as part of the archetype but are not supported by the HTML Cleaner:
h6
address
s (strikethrough)
thead (table header)
caption (table caption)

Attributes:
table: dir, id, summary
th: scope
p: style
li: style
ul: style
ol: style
All block style elements (h1, h2 etc) must have the style attribute

Not clear if we support this already, Youtube also supports html5 param and embed tags for embedding videos
<object height="350" width="425"><param name="movie" value="http://www.youtube.com/v/OdT9z-JjtJk&autoplay=1" /><embed height="350" src="http://www.youtube.com/v/OdT9z-JjtJk&autoplay=1" type="application/x-shockwave-flash" width="425"></embed></object>