Use Binary Merkle Tree instead of a trie (#225)

* Binary tree merkle root.

* Add proofs and verification.

* Clean up debug.

* Use BEEFY addresses instead of pubkeys.

* Use new merkle tree.

* Optimize allocations.

* Add test for larger trees.

* Add tests for larger cases.

* Appease clippy

* Appease clippy2.

* Fix proof generation & verification.

* Add more test data.

* Fix CLI.

* Update README

* Bump version.

* Update docs.

* Rename beefy-merkle-root to beefy-merkle-tree

Co-authored-by: adoerr <0xad@gmx.net>

frame/beefy-mmr/primitives/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "beefy-merkle-tree"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+description = "A no-std/Substrate compatible library to construct binary merkle tree."
+
+[dependencies]
+hex = { version = "0.4", optional = true }
+log = { version = "0.4", optional = true, default-features = false }
+tiny-keccak = { version = "2.0.2", features = ["keccak"], optional = true }
+
+[dev-dependencies]
+env_logger = "0.8"
+hex = "0.4"
+hex-literal = "0.3"
+
+[features]
+debug = ["hex", "log"]
+default = ["std", "debug", "keccak"]
+keccak = ["tiny-keccak"]
+std = ["log/std"]