The C cache (now used only by the reference codecs) moves to
tests/reference and src/uthash.h is deleted. ACL rules and ss-manager's
servers are ListNodes on IntrusiveLists; destroying an element unlinks
it, so the free paths no longer have to remember to. core.h keeps only
ss_ip. test_rule is ported to C++ and also covers literal rules.
The programs now use only the C++ codecs. The C stream/AEAD/AEAD-2022
implementations stay as the reference the differential tests and the C
unit tests compare against. Key derivation and the cipher tables used by
the doc snippets move to src/crypto/keys.{hpp,cpp}.
ss-manager keeps its servers in an ss_list (at most MAX_PORT_NUM,
looked up only on control messages) instead of a uthash table, and
tests/test_manager.py covers add/ping/list/remove end to end.