inheritance semantics in Self 4.0

[Mario Wolczko]

Parent priorities were actually eliminated in 3.0, as was enforcement
of the old privacy semantics.

4.0 makes much more use of copy-downs for sharing, but otherwise not
much has changed.  Privacy has been removed entirely from the
language, but is still supported by the environment as a kind of
structured comment.  The lookup is the same as in 3.0, and is
described in the 3.0 language manual.

4.0 should be out Real Soon Now -- watch this space!
-Mario