run models/testseq.als

FIX: subtle issue with namespaces and multiple modules.  on line 11 of
testseq.als, the invocation SeqLast(s) causes the signature models/testseq/Id
to be visible in the body of a function in seq.als, which does not open or use
testseq.als.  alloy/semantic/ExprTypeCheckVisitor and
alloy/transform/InvocationInlineVisitor were modified to handle this special
case.  