site-generator: Changed the routine used to generate entities in
'HTML::Entities'; see filter function 'xml_entity'
site.cfg: Added root variable 'http_baseurl' which defines the base URL
using 'http'
templates/rss.tpl.xml: RSS template defining the channel and inserting
the 'item' definitions; adjusted to be in step with the PHP version.
templates/shared-item.tpl.xml: RSS template used for each 'item' in an
RSS feed; contains a call to 'HTML::Strip' which turns off the
addition of spaces when removing tags; adjusted to be in step with
the PHP version.
templates/shared-utils.tpl.html: Macro collection used by other
templates; addition of temporay macro 'display_explicit_feed_2'
which generates 'Yes/No' strings to be in step with the PHP version.
