CogVM binaries as per VMMaker.oscog-eem.264/r2678.
Fix snapshot primitive failure in the StackVM and Cogit. The
primitive should fail, not merely return the receiver. Also if in
Cogit, need to back-up instruction pointer on failure.
Make reportMinimumUnusedHeadroom more informative (also print
available headroom).
--
best,
Eliot