Migrate to the 2018 edition (#273)

polkadot/executor/Cargo.toml

@@ -3,8 +3,8 @@ name = "polkadot-executor"
 version = "0.1.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Polkadot node implementation in Rust."
+edition = "2018"
 
 [dependencies]
 substrate-executor = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
-substrate-primitives = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 polkadot-runtime = { path = "../runtime" }

polkadot/executor/src/lib.rs

@@ -17,9 +17,7 @@
 //! A `CodeExecutor` specialisation which uses natively compiled runtime when the wasm to be
 //! executed is equivalent to the natively compiled code.
 
-extern crate polkadot_runtime;
-#[macro_use] extern crate substrate_executor;
-extern crate substrate_primitives as primitives;
+use substrate_executor::native_executor_instance;
 
 native_executor_instance!(
     pub Executor,