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CogVM binaries as per VMMaker.oscog-eem.134/r2502

Ensure the unix run scripts set SQUEAK_PLUGINS if unset.

Fix remaining bug in context access fixes of VMMaker.oscog-eem.119.

stObject:at: and stObject:at:put: need to use stackPointerForMaybeMarriedContext:

not fetchStackPointerOf:, since the context's stack pointer may be stale.

Fix send trace printing.  Interpreter sends need also to be printed.

(A better fix is probably to redo sendBreakpoint: but this will serve for now).

N.B. this reassigns the sendtrace flag values.

Add primitiveNotEquivalent with prim # 169.