Fixed parent_reference bug [sequel-datasets]
Extracted BaseEntity.to_h to a Mapper method
Transaction uses ObjectHistory class. Still, no aggregate update though [sequel-datasets]
Entity.fetch_from_transaction(:uuid) return a SearchResult iterator [sequel-datasets]
Merge branch 'sequel-datasets' of git://github.com/nandosola/sequel-uow into sequel-datasets

Conflicts:
	lib/base_entity.rb
	lib/mapper.rb
	lib/uow/transaction.rb

On branch sequel-datasets