separate trie from util and make its dependencies into libs:

* bytes
* hashdb
* memorydb
* nibbleslice
* nibblevec

ethcore/src/tests/evm.rs

@@ -14,6 +14,7 @@ use rustc_hex::FromHex;
 
 use bigint::hash::H256;
 use util::*;
+use bytes::BytesRef;
 
 evm_test!{test_blockhash_eip210: test_blockhash_eip210_jit, test_blockhash_eip210_int}
 fn test_blockhash_eip210(factory: Factory) {

ethcore/src/tests/helpers.rs

@@ -23,6 +23,7 @@ use client::{BlockChainClient, Client, ClientConfig};
 use bigint::prelude::U256;
 use bigint::hash::H256;
 use util::*;
+use bytes::Bytes;
 use spec::*;
 use account_provider::AccountProvider;
 use state_db::StateDB;