Fixed IssueAssetTransactions not being constructed with signature.
Fixed incorrect MessageTransactionData constructors.
Refactored various transactions to remove duplicate code.
e.g. in CancelOrderTransaction.process() use getCreator() instead of explicit repository call.
Added name_reference to BuyNameTransactions HSQLDB table.
Fixed incorrect SQL in HSQLDBMultiPaymentTransactionRepository.
More unit tests!
Fixed wrong data length in CancelOrderTransactionTransformer.
Fixed wrong data length in CreateOrderTransactionTransformer.
Fixed missing payment bytes in MultiPaymentTransactionTransformer.toBytes();
* Added AssetData transfer object
* Added IssueAssetTransactionData transfer object
* Reworked qora.assets.Asset into business layer object
* Reworked qora.transaction.IssueAssetTransaction into business layer object
* Added corresponding AssetRepository and support in TransactionRepository et al
* Fixed BlockChain in line with asset changes
* Some renaming inside GenesisTransaction to reflect use of transfer object, not business object
* Business transaction objects now take Repository param
* Moved HSQLDB transaction repositories into a sub-package
* Changed HSQLDBSaver.execute(Connection connection) to .execute(Repository repository) to fix visibility issues
and allow repository more control in the future if need be
* Changed from "return null" statements in HSQLDB repositories to throw DataException when an error occurs.
Better to throw than to silently return null?
* Added static version of PublicKeyAccount.verify() for when a repository-backed PublicKeyAccount is not needed
* Fixed getter/setter code template incorrectly producing "this.this.field = param"
