Implement support for renaming runtime api functions (#2160)

* Implement support for renaming runtime api functions

* Redelete the wasm files

* FIxes test

* Fix test correctly...

* Bring back old `authorities`

* Tag as deprecated

* Fixes compilation on WASM

* Add missing method implementations

* Fixes tests

* Increase `spec_version`

substrate/node-template/runtime/src/lib.rs

@@ -241,6 +241,10 @@ impl_runtime_apis! {
 		fn initialize_block(header: &<Block as BlockT>::Header) {
 			Executive::initialize_block(header)
 		}
+
+		fn authorities() -> Vec<AuthorityId> {
+			panic!("Deprecated, please use `AuthoritiesApi`.")
+		}
 	}
 
 	impl runtime_api::Metadata<Block> for Runtime {