SAK-23875

Add the validation and sanitization code from KNL-1105 into the web content tool 
to ease back-porting in case folks need the new features in a hurry.




git-svn-id: https://source.sakaiproject.org/svn/web/trunk@128949 66ffb92e-73f9-0310-93c1-f5514f145a0a