Consensus Engines Implementation: Aura (#911)

* Generalize BlockImport

 - move ImportBlock, BlockOrigin, ImportResult into shared sr-primitives
 - let Consensus provide  and  traits again
 - update consensus traits to latest development
 - implement traits on client::Client, test_client::TestClient
 - update RHD to use the new import_block API

* Move ImportBlock into consensus-common
* Send import notification in aura tests
* Integrating aura into service
* Make Signatures more generic
* Aura Block Production with the given key
* run aura on the thread pool
* start at exact step start in aura
* Add needed wasm blob, in leiu of better solutions.
* Make API ids consistent with traits and bring upstream for sharing.
* Add decrease_free_balance to Balances module
* Encode `Metadata` once instead of two times
* Bitops include xor
* Upgrade key module.
* Default pages to somewhat bigger.
* Introduce upgrade key into node
* Add `Created` event

substrate/srml/support/src/dispatch.rs

@@ -208,7 +208,7 @@ macro_rules! decl_module {
 			[
 				$($t)*
 				$(#[doc = $doc_attr])*
-				fn $fn_name(root $( , $param_name : $param )* ) -> $result { $( $impl )* }
+				$fn_vis fn $fn_name(root $( , $param_name : $param )* ) -> $result { $( $impl )* }
 			]
 			$($rest)*
 		);