[m-rev.] for review: help diagnose non-fully-qualified references to use_module'd modules

[Zoltan Somogyi]

This should help users in Sean's position.

For review by anyone.

I intend to put the contents of the modules affected by this change
into a more logical order, but will do that after review, in order
to keep irrelevant changes out of the diff.

Zoltan.
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