fixed it by looking for funny things that deviated from
the sameples, and doing various recommended safe things,
and found a few sql errors, and one by one the crashes
went away.
The new wxWidgets just seems less tolerant of little careless
stuff that is not right.
Remade hashing according to the dry principle,
eliminating much code repetition.
Introduced c++20 "concepts" to radically reduce
verbose and incomprehensible template metacode.
modified: src/db_accessors.h
modified: src/ristretto255.h
modified: src/testbed.cpp
