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

beacon_node/rpc/Cargo.toml

@@ -11,7 +11,7 @@ network = { path = "../network" }
 eth2-libp2p = { path = "../eth2-libp2p" }
 version = { path = "../version" }
 types = { path = "../../eth2/types" }
-eth2_ssz = { path = "../../eth2/utils/ssz" }
+eth2_ssz = "0.1"
 protos = { path = "../../protos" }
 grpcio = { version = "0.4", default-features = false, features = ["protobuf-codec"] }
 clap = "2.32.0"