item-procs-postgresql.xql

1. I made it possible to let content_template.new(), and its PG equivalent,
create a revision of the template by simply providing the template in the 'text'
param.
2. Bug-fixed content::init, content::get_content and some other procs related
to the index.vuh in the CR. Virtual URLs are now more or less supported for items
of any content type if they have a content template associated with them.
If a content item associates a template to it (by registering it), it will have precedence
over the type's template. It will transparently act as a default, in other words.