Facia tool: html sanitizer

Sanitizes html in headlines, trailtext, etc:
* balances any open & closing tags
* strips everything including and after a `<script...`
If all Stephan is doing is removing `script` tags and making sure tags are balanced, I think it's fine to use the browser to parse the HTML tree if it's preferable in this case to avoid the overhead of the HTTP request.

Completely agree, though, that if it gets any more complicated it should just be relegated to `TagSoup.clean`