update Sigil to 4.3.0
speed up visiting members of a dynamic jil object when serializing
quick and dirty test to prove the previous commit is actually faster; it is, about 35% faster in this test
can't keep this test around for dynamics; hurts real-world perf
speed up json encoding of members in serialize dynamic + test
can't leave this test in; same reason as last time
more jsonescape tuning
vs really wants to change this SLN
2.3.0