Item12327: better support for StrikeOne

StrikeOne tends to manipulate a lot of inline JS, thus messing up our
precious signatures. Introduce code to ignore StrikeOne boilerplate code when
generating/verifying signatures, and make sure it doesn't get filtered.


git-svn-id: http://svn.foswiki.org/trunk/SafeWikiPlugin@16450 0b4bb1d4-4e5a-0410-9cc4-b2b747904278