Record name and constructor are in the outer namespace, fields in the
nested namepsace. Private names in the nested namespace is visible from
the outer namespace. Fixes#183
Also remove the 'nested' flag on INamespace, since it was only there for
records, and not really the right way to do things. The nested namespace
name is now given in the IRecord constructor (a front end might not want
to use a new namespace after all).
