* core: grandpa: migrate to grandpa 0.7
* core: grandpa: store current round votes and load them on startup
* core: grandpa: resend old persisted votes for the current round
* core: grandpa: store base and votes for last completed round
* core: grandpa: fix latest grandpa 0.7 changes
* core: grandpa: update to grandpa 0.7.1
* core: grandpa: persist votes for last two completed rounds
* core: grandpa: simplify VoterSetState usage
* core: grandpa: use Environment::update_voter_set_state
* core: grandpa: fix aux_schema test
* core: grandpa: add docs
* core: grandpa: add note about environment assumption
* core: grandpa: don't update voter set state on ignored votes
* core: grandpa: add test for v1 -> v2 aux_schema migration
* core: grandpa: add test for voter vote persistence
* core: grandpa: use grandpa 0.7.1 from crates.io
* core: grandpa: use try_init in test
* core: grandpa: add comment about block_import in test
* core: grandpa: avoid cloning HasVoted
* core: grandpa: add missing docs
* core: grandpa: cleanup up can_propose/prevote/precommit
* Make use of parity-codec "derive" crate feature
* Bump impl_version
* Update wasm files and Cargo.lock files
* Transferred to parity_codec derive feature for the rest of the crates
* Update wasm binaries and lock files
* Update core and node wasm binaries
* core: grandpa: move consensus_changes to its own submodule
* core: grandpa: move justification to its own submodule
* core: grandpa: move environment to its own submodule
* core: grandpa: move block import to its own submodule
André Silva