* Replace default hasher (Double-SHA256) with domain seperated blake2b
* Replace all hashes with domain seperated blake2b
* Update the genesis blocks
* Replace OP_HASH256 with OP_BLAKE2B
* Fix the merkle tree by appending zeros instead of duplicating the hash when there is 1 branch left
* Update tests
* Add a payloadHash function
* Update gitignore to ignore binaries
* Fix a bug in the blake2b opcode