New HTML message body options for Mailnews
Provide a work around / fix for some of the security and usability problems that HTML mails currently impose, by not rendering everything the sender throws at the user.
This class removes every HTML tag/attribute that is not explicitly allowed from the source.
Adding new class to build
r=akk, sr=jst
git-svn-id: svn://10.0.0.236/trunk@119118 18797224-902f-48f8-a5cc-f745e15eee43