Simplify BABE pre-digest definitions (#5289)

* Init vrf crate without type alias

* Generic PreDigest definition for BABE

* Fix BABE vrf interface change

* Missing default-features def in sp-consensus-babe

* Fix sp-consensus-babe compile

* frame-babe: fix type inference

* Unify type definitions of vrf output/proof and randomness

* frame-babe: fix tests

* Bump node impl version

* Update cargo lock

* Derive Copy for RawVRFOutput and RawVRFProof

* Fix duplicated derive

Co-authored-by: Gavin Wood <gavin@parity.io>

substrate/primitives/consensus/vrf/src/lib.rs

@@ -0,0 +1,20 @@
+// Copyright 2019-2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Primitives for VRF-based consensus engines.
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub mod schnorrkel;