separate trie from util and make its dependencies into libs:

* bytes
* hashdb
* memorydb
* nibbleslice
* nibblevec

ethcore/src/blockchain/best_block.rs

@@ -16,7 +16,7 @@
 
 use bigint::prelude::U256;
 use bigint::hash::H256;
-use util::Bytes;
+use bytes::Bytes;
 use header::BlockNumber;
 
 /// Best block info.

ethcore/src/blockchain/blockchain.rs

@@ -25,6 +25,7 @@ use heapsize::HeapSizeOf;
 use bigint::prelude::U256;
 use bigint::hash::{H256, H2048};
 use parking_lot::{Mutex, RwLock};
+use bytes::Bytes;
 use util::*;
 use rlp::*;
 use header::*;

ethcore/src/blockchain/generator/block.rs

@@ -16,7 +16,7 @@
 
 use rlp::*;
 use bigint::hash::{H256, H2048};
-use util::bytes::Bytes;
+use bytes::Bytes;
 use header::Header;
 use transaction::SignedTransaction;
 

ethcore/src/blockchain/generator/complete.rs

@@ -15,7 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 use bigint::hash::H256;
-use util::bytes::Bytes;
+use bytes::Bytes;
 use views::BlockView;
 
 #[derive(Default, Clone)]

ethcore/src/blockchain/generator/generator.rs

@@ -16,7 +16,7 @@
 
 use bigint::prelude::U256;
 use bigint::hash::H2048;
-use util::Bytes;
+use bytes::Bytes;
 use header::BlockNumber;
 use transaction::SignedTransaction;
 use super::fork::Fork;