Fix typo in documentation.
Reorder code.
Change from [] syntax to list(), since we're using the blist list type.
Move Merkle-tree code into its own module, and begin process of implementing MerkleList and MerkleProof containers.
MerkleList is serializable, not MerkleNode.
deserialize_outpoint calls a class method, so it needs to be a class method itself.
deserialize_transaction is no longer required now that the Block class does not handle deserialization of the Block/Transaction Merkle-tree.