CogVM binaries as per VMMaker.oscog-eem.238/r2637

Restore ThreadedFFIPlugin wanting COGMTVM to be determined on

command line. �Probably broke in VMMaker.oscog-eem.218

Fix bug in changeClass:from: so that if receiver has long header and

class is compact, receiver still gets compact class field set, not

cleared. �No matter what header an instance has, if its class is

compact it should have the compact class index set.