r11262: Try to get the equivalent of a subcontext in pidl ethereal conformance

r11262: Try to get the equivalent of a subcontext in pidl ethereal conformance
files working.  It doesn't quite work though.  (-:

This patch also allows a struct.field format to be used in an IMPORT
statement instead of a type name.

Jelmer, what do you think?
(This used to be commit d770f853475d12a33d23fc86ab30223dfde22dd7)