remove dependency on CGI.pm and use HTML::Entities

since all we are using CGI for is to encode HTML entities we should
instead use a more specific module to do this: HTML::Entities. so
we don't end up depending on an 8,000 line module for a simple call
(and i'm probably going to refactor CGI.pm to use HTML::Entities
for its escapeHTML function anyway)

---------------------

Well i was hoping this might make a good case-study for convering
a CGI.pm dependency to Template::Toolkit, but it seems the bulk
of the HTML is *already* using Template::Toolkit and all that is left
of CGI.pm is the call to escapeHTML. So i've replaced that with the
HTML::Entities module and thus removed the CGI.pm dependency

No automated tests here, but looks fine in the browser.