Custom RPC methods for DummyOrdered pallet (#317)

* RPC for DummyOrdered

* add test for RPC

* proof returned by RPC is Vec<<Vec<u8>>>.encode()

* retrieval -> receiving

* bp-runtime crate

* bp-runtime supports no_std

* cargo fmt --all

* jsonrpc_core::BoxFuture

* Update modules/message-lane/rpc/Cargo.toml

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* messageLane_ prefix for RPC methods

* Update primitives/runtime/Cargo.toml

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update primitives/runtime/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

bridges/primitives/runtime/src/lib.rs

@@ -0,0 +1,25 @@
+// Copyright 2019-2020 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Primitives that may be used at (bridges) runtime level.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+/// Id of deployed module instance. We have a bunch of pallets that may be used in
+/// different bridges. E.g. message-lane pallet may be deployed twice in the same
+/// runtime to bridge ThisChain with Chain1 and Chain2. Sometimes we need to be able
+/// to identify deployed instance dynamically. This type is used for that.
+pub type InstanceId = [u8; 4];