LC8 IDE publish-and-subscribe

[Mark]

The new LC8 IDE implements the publish-and-subscribe pattern,
but it looks like it isn't designed to be extensible. It's extensible
right now because revIDEMessageIsValid() always returns true.

Q: assuming that the validity check was an interim test to make sure
the IDE didn't fall on its face, can we rely on this mechanism as a way
to register callback events in the IDE, and thus extend and modify
the IDE?

-- 
 Mark Wieder
 ahsoftware at gmail.com