[htmltmpl] Patch for new option "force_untaint"

[Sven N. <sve...@sv...>]

Hi,

I have opened a new bug (#23592) on rt.cpan.org for a new feature request:
The "force_untaint" option. This option makes sure that no tainted values
are set in the template.
If set to 1, only TMPL_VARs with no ESCAPE-attribute must be untainted,
if set to 2, every TMPL_VAR must be untainted.

I have attached a patch to the bug that implements this feature.

Please let me know what you think. I believe this would be very helpful in
preventing cross-site-scripting (CSS) bugs.

Regards,
-Sven Neuhaus