New mining framework.

Fixes #756.

ethcore/src/client/test_client.rs

@@ -31,6 +31,7 @@ use block_queue::BlockQueueInfo;
 use block::{SealedBlock, ClosedBlock};
 use executive::Executed;
 use error::Error;
+use engine::Engine;
 
 /// Test client.
 pub struct TestBlockChainClient {
@@ -249,7 +250,7 @@ impl BlockChainClient for TestBlockChainClient {
 	}
 
 	fn prepare_sealing(&self, _author: Address, _gas_floor_target: U256, _extra_data: Bytes, _transactions: Vec<SignedTransaction>) -> (Option<ClosedBlock>, HashSet<H256>) {
-		(None, vec![])
+		(None, HashSet::new())
 	}
 
 	fn try_seal(&self, block: ClosedBlock, _seal: Vec<Bytes>) -> Result<SealedBlock, ClosedBlock> {
@@ -404,4 +405,8 @@ impl BlockChainClient for TestBlockChainClient {
 			best_block_number: self.blocks.read().unwrap().len() as BlockNumber - 1,
 		}
 	}
+
+	fn engine(&self) -> &Engine {
+		unimplemented!();
+	}
 }