updated the object lister params and docs

The --show argument now takes +,^,- as prefixes to append, prepend, and remove
fields from the default set.

The --help argument now shows indirect properties one step away.

When running "ur list objects", the namespace of the
--subject-class-name is used automatically before loading.

Class properties now have an is_undocumented and a doc_position field
to help with automatic documentation.