Changes

Summary

1. merged
2. added lemmas irreflp_{less,greater} to preorder and {trans,irrefl}_mult{,p} to Multiset
3. redefined less_multiset to be based on multp
4. added lemmas multp_code_eq_multp and multeqp_code_eq_reflclp_multp
5. added lemmas multp_cancel, multp_cancel_add_mset, and multp_cancel_max
6. added lemmas multp_implies_one_step, one_step_implies_multp, and subset_implies_multp
7. added lemma wfP_multp
8. added lemma mono_multp
9. added Multiset.multp as predicate equivalent of Multiset.mult
10. address problems with launch4j and jdk-17 (see also 41d009462d3c);
11. more robust build on midrange hardware;
12. clarified tests: omit somewhat pointless (unstable) results;
13. proper fields for gnuplot (amending b614e3e4146a);
14. tuned output;
15. tuned;