Simple WebSockets notification about new request (#1202)

* Splitting methods requiring signing into separate trait

* Single place where RPC apis are created.

* Separating eth_filter

* Separating eth_signing

* Stubs for Personal Signer methods

* Test for EthSigningQueueClient

* TransactionConfirmation API

* Exposing PersonalSigner API

* Defining ApiSets dependent on context

* Removing types

* Supporting sending notification to WS connected SystemUIs

* Sending a notification on every new messages

* Adding logs to signing queue

* Shutting down broadcaster

* Refactoring the signing queue

* Fixing wait loop in case of spurious wake-ups.

parity/signer.rs

@@ -51,7 +51,7 @@ fn do_start(conf: Configuration, deps: Dependencies) -> SignerServer {
 	});
 
 	let start_result = {
-		let server = signer::ServerBuilder::new();
+		let server = signer::ServerBuilder::new(deps.apis.signer_queue.clone());
 		let server = rpc_apis::setup_rpc(server, deps.apis, rpc_apis::ApiSet::SafeContext);
 		server.start(addr)
 	};