* 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
* First pass at iterative siphash
* Generalizing our siphash24 implementation slightly to make it friendlier to repeated hashing
* Block siphash algorithm, Cuckaroo placeholder
* Cuckaroo validator, still needs to be tested with vectors from the @tromp implementation
* Working cuckaroo validation with test vectors for cuckaroo19, will add cuckaroo29 vectors when a lean or mean implementation can find some solutions
