(PUP-501) Check that empty titles creates no resources

When a title array is empty, there are no resources created.
(PUP-501) Check virtual and exported resources

This adds checks for the specification's assertions that virutal and
exported resources are not in the produced catalog, but are available
for later operations (realization) and reference (reading a parameter
value). This cannot check that the exported resources are made available
to catalog processors, since that is implementation dependent.

In order to check this the compile_to_catalog method needed to be
changed to filter out expoerted resources, just like the catalog
indirection does. This required a change to the create_resources test.
(PUP-501) Check all of the features together

This adds a combined example of most of the features being used
together: title expressions, type expressions, splatted parameters,
exported resource, and resource reference.