Heavily restructure repo

Separate most modules into crates

beacon_chain/utils/hashing/src/lib.rs

@@ -0,0 +1,8 @@
+extern crate blake2_rfc;
+
+use self::blake2_rfc::blake2b::blake2b;
+
+pub fn canonical_hash(input: &[u8]) -> Vec<u8> {
+    let result = blake2b(64, &[], input);
+    result.as_bytes()[0..32].to_vec()
+}