Authenticator signature must cover both state hash and tx hash

[MastaP]

Currently it only signs tx hash

[martti007]

Change the aggregator submit request to contain following data: (state id, public key, source state hash, transaction hash, signature)

State id is hash which is calculated as H(CBOR([source state hash, public key])). Signature is created on the hash H(CBOR([source state hash, transaction hash])). This ensures that we can check if state id is correct and prevents hijacking of state id.