* PoW context is now properly picked depending on the chain type,
edge bits and block height. Height const for T4 hard fork leaving
a couple weeks to have miners in place. Removed now unused Cuckoo context.
* Simplified block siphash
* Fix servers crate compilation
* Tiny bit cleaner block siphash. Maybe.
* Cuckatoo min edge bits update for T4 and mainnet
* Fix header size tests, Cuckatoo31 default means one more bit per edge
* Remove redundant param from verify_size
* cuck placeholder
* rustfmt
* cuckatoo, early days
* rustfmt
* data structures are in place, siphash key creation is consistent with @tromp
* solver in place, (not yet working)
* cuckatoo test solver working with test nonce
* rustfmt
* update solver to remove adjacency list removals
* verifier functioning
* rustfmt
* Proper error handing in Cuckatoo module, couple of tests
* modify cuckoo/cuckatoo solvers and verifiers to function identically, in advance of trait refactoring
* rustfmt
* refactor PoW context into trait, default to using cuckoo context
* rustfmt
* create macros for integer casting/unwraps
* don't instantiate structs when just verifying, add test validation vector for cuckatoo 29
* rustfmt
* don't init cuckoo structs if just validating
* test fix
* ensure BH hashing for POW is only done within miner/validators
