Test for #239.
    Added new test category for testting POG on complete models.
Reduce duplicate test code.
Update result files with additional substitutions.
Major changes to the visitor based on a newer better Isabelle/CML, breaks compatibility with prior versions
Merge remote-tracking branch 'origin/sdf' into newpog
Initial version of a kill Isabelle button.
Added invariant to assumptions in Satisfiability obligation.
fixed Models test since it stopeed running for some reason.
Fixed regression error where precondition was no longer set if there was no invariant.
Update test results for sat op with invariant in assumption.