* Additional protections against HTML breakage in table parsing

* Additional protections against HTML breakage in table parsing
Avoid splitting table cells on "||" appearing in HTML tag attributes.
Bad tag nesting is still possible, but this should keep things from
being split unexpectedly in the middle of an element, and might
avoid some potential injection points.
See http://mail.wikipedia.org/pipermail/wikitech-l/2006-April/034637.html