Expanse compatibility (#2369)

* Add support for Expanse.

* Fix build.

* Refactor to be able to alter the eth subprotocol name

* Fix JSON.

* Support exp hardfork.

* Fix exp json again.

* Fixed test

* Fix tests.

parity/params.rs

@@ -29,6 +29,7 @@ pub enum SpecType {
 	Testnet,
 	Olympic,
 	Classic,
+	Expanse,
 	Custom(String),
 }
 
@@ -47,6 +48,7 @@ impl str::FromStr for SpecType {
 			"frontier-dogmatic" | "homestead-dogmatic" | "classic" => SpecType::Classic,
 			"morden" | "testnet" => SpecType::Testnet,
 			"olympic" => SpecType::Olympic,
+			"expanse" => SpecType::Expanse,
 			other => SpecType::Custom(other.into()),
 		};
 		Ok(spec)
@@ -60,6 +62,7 @@ impl SpecType {
 			SpecType::Testnet => Ok(ethereum::new_morden()),
 			SpecType::Olympic => Ok(ethereum::new_olympic()),
 			SpecType::Classic => Ok(ethereum::new_classic()),
+			SpecType::Expanse => Ok(ethereum::new_expanse()),
 			SpecType::Custom(ref filename) => {
 				let file = try!(fs::File::open(filename).map_err(|_| "Could not load specification file."));
 				Spec::load(file)

parity/run.rs

@@ -148,6 +148,11 @@ pub fn execute(cmd: RunCmd) -> Result<(), String> {
 		Some(id) => id,
 		None => spec.network_id(),
 	};
+	if spec.subprotocol_name().len() != 3 {
+		warn!("Your chain specification's subprotocol length is not 3. Ignoring.");
+	} else {
+		sync_config.subprotocol_name.clone_from_slice(spec.subprotocol_name().as_bytes());
+	}
 	sync_config.fork_block = spec.fork_block();
 
 	// prepare account provider