* [WIP] support multiple validators in an attestation and rework runtime

* [WIP] More fixes to nostd and basic new AttestationRecord

* [WIP] finish runtime integration

* [WIP] Fix deps

* [WIP] some compile fixes

* Make consensus compile

* Make everything compile

* Fix authoring

* Fix doctest complain

* [WIP] update runtime to newest version

* Port crypto to edition 2018

* Port everything else and make it compile

* Fix start_time

* Fix compile

* Update bls version

* Re-introduce aggregate signature support

* Move DigestItem to a separate mod

* CompatibleExtrinsic trait

* Expose API for validator id from attestation

* CompatibleExtrinsic impl

* Save and load latest attestations

* note_block for LatestAttestation

* Expose last finalized/justified slot from runtime

* Implement LMD-GHOST's is_new_best

* Update substrate reference

* Finish LMD-GHOST integration

* Remove old unused lmd-ghost crate

* README: LMD-GHOST is integrated

* Switch to own DigestItem impl

* Fix consensus compile

* H256 -> Self::Hash

But note that this is incorrect according to eth2.0-specs BLS definition. It should be 48 bytes (and it's a G1, not G2).

* Init lmd-ghost crate

* Add H384 primitive

* Rename primitives -> shasper-primitives

* Implement justified head

* Finish a draft implementation of lmd-ghost

* Add docs for lmd-ghost

* Add license header for primitives

* Update substrate git version

* Fix wasm compile

* Implement GetNodeBlockType and GetRuntimeBlockType for Runtime

* Mark runtime as public

* Path fixes

* Fix transaction pool definition

* Fix metadata and service component type updates

* Fix genesis and queue compile

* Fix cli compile

* Update substrate version

* Fix ssz compile

* Fix runtime compile

* Fix std utils compile

* Fix service compile

* Fix ssz hash tests

* Remove Travis CI

* Implement ssz merkle root function

* Implement object hash function

* Add a hash-derive implementation

* Implement spec_hash for Vec

* Move type parameter to fn

* Integrate ssz_hash into runtime