added proof reconstructon for Z3,
added certificates for simpler re-checking of proofs (no need to invoke external solvers),
added examples and certificates for all examples,
removed Unsynchronized.ref (in smt_normalize.ML)
(benchmark Isabelle
:extrasorts ( T1)
:extrapreds (
(up_1)
)
:assumption (not (or up_1 (not up_1)))
:formula true
)