Expose block random seed and timestamp to contract ABI (#1630)

* Expose block random seed and timestamp to contract ABI

* Add tests

* Bump spec version

substrate/node/runtime/src/lib.rs

@@ -65,8 +65,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 22,
-	impl_version: 22,
+	spec_version: 23,
+	impl_version: 23,
 	apis: RUNTIME_API_VERSIONS,
 };
 

substrate/node/runtime/wasm/Cargo.lock

@@ -1201,6 +1201,7 @@ dependencies = [
  "srml-balances 0.1.0",
  "srml-support 0.1.0",
  "srml-system 0.1.0",
+ "srml-timestamp 0.1.0",
  "substrate-primitives 0.1.0",
 ]