Removed .LRN dependencies from calendar (essentially the view include
scripts only worked from within .LRN or calendar itself). Did a bunch of
clean-up of stuff being computed by portlets that are totally ignored by the
calendar include scripts. If the semantics are wanted, they should be put
into the calendar package itself. Switched a bunch of stuff to properly use
export_vars, and to generate links inline rather than subst an awkward
template. Got rid of the use of site_node_object_map in calendar, because
calendars have a perfectly usable package_id in the data model (should really
be rewritten to use package_id in the underlying acs_objects row), and the
URLs generated by site_node_object_map are just as easily generated from this
package id. Bonus: site nodes are cached, the site_node_object_map is not.
