Fix warnings in substrate (#1523)

* Fix warnings in substrate

* More warnings removed and wasm updated

* Fixes error on stable and grumbles

* Update wasm files

* Add links to the github issue for replacing `error-chain`

substrate/srml/support/src/event.rs

@@ -268,7 +268,7 @@ macro_rules! __events_to_metadata {
 	}
 }
 
-/// Constructs an Event type for a runtime. This is usually called automatically by the 
+/// Constructs an Event type for a runtime. This is usually called automatically by the
 /// construct_runtime macro. See also __create_decl_macro.
 #[macro_export]
 macro_rules! impl_outer_event {
@@ -441,6 +441,7 @@ macro_rules! __impl_outer_event_json_metadata {
 #[allow(dead_code)]
 mod tests {
 	use super::*;
+	use serde_derive::Serialize;
 
 	mod system {
 		pub trait Trait {

substrate/srml/support/src/lib.rs

@@ -38,7 +38,6 @@ extern crate substrate_inherents as inherents;
 #[macro_use]
 extern crate pretty_assertions;
 #[cfg(feature = "std")]
-#[macro_use]
 extern crate serde_derive;
 #[cfg(test)]
 #[macro_use]