Post trigger, this change will use all 128 bytes of previous block's signature when
calculating/validating next block's "minter" signature (itself the first 64 bytes of a block signature).
Prior to trigger, current behaviour is to only use first 64 bytes of previous block's
signature, which doesn't encompass transactions signature.
New block sig code should help reduce forking and help improve transactional
security.
Added "newBlockSigHeight" to blockchain.json but initially set to block 999999
pending decision on when to merge, auto-update, go-live, etc.
Group owner now derived from CREATE_GROUP transaction creator's public key.
Added 'reduced' group name to GroupData, with corresponding change to DB.
Renamed GroupData.getIsOpen() to simply isOpen().
Tidied up CreateGroupTransactionData, adding 'reduced' group name.
Renamed getIsOpen() to simply isOpen().
Added code to generated reduced group name when building genesis block.
Added Group.MIN_NAME_SIZE of 3.
DB tables changed to add reduced_group_name where appropriate,
removing owner where necessary.
Added GroupRepository.reducedGroupNameExists(String).
Fixed up test blockchain configs in src/test/resources/test-chain-v2*.json.
Owner now derived from issuer's public key.
Maximum asset name length reduced to 40 characters.
Repository table changes.
"owner" removed from test blockchain configs and "issuerPublicKey" used instead
where applicable.
Some getters in the form of "getIs___()" renamed to simply "is____()".
