Make ad_html_security_check configurable
ad_html_security_check has now three optional attributes
to make it configurable for different situations
-allowed_tags
-allowed_attributes
-allowed_protocols
If these attributes are not specified, the behavior is exactly like
before. This change makes it also easier to regression test this
function, since the behavior does not necessarily depend on a site's
parameter settings.
The function was also modernized, new regression tests were added.