add failing test for variable with import

Currently inner variable assignments
fails to work correctly if issued as
part of the import-special syntax.
use ontology argument in redefine by import.
add pseudo-set class

The original Set in rubys stdlib has problems
if the objects change while a member of the set.
PseudoSet does not have the same problems, as it
will return the member-object and so somewhat
support a singleton nature.
use pseudoset in project.
change equality of prefix and class

Both strictly rely on the ontology they
are being defined in, so we will refer to
that when building an identifier.
Merge pull request #3 from 0robustus1/fix_import_special_handling

Fix import special handling