Make runtime api generate version and identifier information (#1226)

* Make `decl_runtime_apis!` implement `RuntimeApiInfo` for all runtime
apis

* Make the runtime side generate the info constants as well

* Make `RuntimeApiInfo` implementation use the correct generics

* Adds a test for the runtime api info stuff

* Remove duplicated code by using block from `test-client`

* Adds `compile_fail` tests for `api_version`

* Adds documentation for `api_version`

* Make `impl_runtime_apis!` generate `RUNTIME_API_VERSIONS`

* Update documentation and tests for `RUNTIME_API_VERSIONS`

* Implement `has_api` by using the `RuntimeApiInfo`

* Make `impl_runtime_apis` check that trait identifiers are unique

* Prefix all runtime api function with the corresponding trait

So `execute_block` will be called `Core_execute_block`.
This makes it possible to have traits implement a function with the
same name.

* Rebase master

* Update after master rebase

substrate/core/client/src/genesis.rs

@@ -91,7 +91,7 @@ mod tests {
 			Some(&InMemoryChangesTrieStorage::new()),
 			&mut overlay,
 			&executor(),
-			"initialise_block",
+			"Core_initialise_block",
 			&header.encode(),
 			ExecutionStrategy::NativeWhenPossible,
 		).unwrap();
@@ -102,7 +102,7 @@ mod tests {
 				Some(&InMemoryChangesTrieStorage::new()),
 				&mut overlay,
 				&executor(),
-				"apply_extrinsic",
+				"BlockBuilder_apply_extrinsic",
 				&tx.encode(),
 				ExecutionStrategy::NativeWhenPossible,
 			).unwrap();
@@ -113,7 +113,7 @@ mod tests {
 			Some(&InMemoryChangesTrieStorage::new()),
 			&mut overlay,
 			&executor(),
-			"finalise_block",
+			"BlockBuilder_finalise_block",
 			&[],
 			ExecutionStrategy::NativeWhenPossible,
 		).unwrap();
@@ -157,7 +157,7 @@ mod tests {
 			Some(&InMemoryChangesTrieStorage::new()),
 			&mut overlay,
 			&executor(),
-			"execute_block",
+			"Core_execute_block",
 			&b1data,
 			ExecutionStrategy::NativeWhenPossible,
 		).unwrap();
@@ -182,7 +182,7 @@ mod tests {
 			Some(&InMemoryChangesTrieStorage::new()),
 			&mut overlay,
 			&executor(),
-			"execute_block",
+			"Core_execute_block",
 			&b1data,
 			ExecutionStrategy::AlwaysWasm,
 		).unwrap();
@@ -208,7 +208,7 @@ mod tests {
 			Some(&InMemoryChangesTrieStorage::new()),
 			&mut overlay,
 			&Executor::new(),
-			"execute_block",
+			"Core_execute_block",
 			&b1data,
 			ExecutionStrategy::NativeWhenPossible,
 		).unwrap();