Publish ssz_types (and deps) to crates.io (#468)

* Rename `hashing` crate to `eth2_hashing`

* Add license, desc to eth2_hashing Cargo.toml

* Remove merkle root from eth2 hashing

* Remove old benches folder (zombied from old branch)

* Add docs to eth2_hashing

* Prepare tree_hash for publishing on crates.io

* Update deps to use crates.io instead of paths

* Update all crates to pull ssz from crates.io

* Remove cached_tree_hash, add patches to manifest

* Fix compile error in benches

* Remove unused code

* Fix fake_crypto compile error

validator_client/Cargo.toml

@@ -14,9 +14,9 @@ path = "src/lib.rs"
 
 [dependencies]
 bls = { path = "../eth2/utils/bls" }
-eth2_ssz = { path = "../eth2/utils/ssz" }
+eth2_ssz = "0.1"
 eth2_config = { path = "../eth2/utils/eth2_config" }
-tree_hash = { path = "../eth2/utils/tree_hash" }
+tree_hash = "0.1"
 clap = "2.32.0"
 grpcio = { version = "0.4", default-features = false, features = ["protobuf-codec"] }
 protos = { path = "../protos" }