Rust Cuckatoo for verifier and test-miner (#1558)

* 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

servers/src/common/types.rs

@@ -42,7 +42,7 @@ pub enum Error {
 	/// Error originating from wallet API.
 	Wallet(wallet::Error),
 	/// Error originating from the cuckoo miner
-	Cuckoo(pow::cuckoo::Error),
+	Cuckoo(pow::Error),
 }
 
 impl From<core::block::Error> for Error {
@@ -62,8 +62,8 @@ impl From<p2p::Error> for Error {
 	}
 }
 
-impl From<pow::cuckoo::Error> for Error {
-	fn from(e: pow::cuckoo::Error) -> Error {
+impl From<pow::Error> for Error {
+	fn from(e: pow::Error) -> Error {
 		Error::Cuckoo(e)
 	}
 }