v0.9.0

• Output VO values as nested dicts instead of a forced flat structure
• Enclose DAOs within repositories to encourage DB interaction solely through repos
• Remove remove method from repository to discourage hard deletes
• Manage concurrency with Aggregate versions
• Add MessageDB Event store adapter
• Add stand-in Memory Event store
• Introduce EventSourced Aggregates and Event Handlers
• Introduce EventSourced Repositories
• Allow filtering of messages from their origin stream
• Allow Event Handlers to listen to other streams and ALL streams
• Allow Command Handler methods to handle any event
• Wrap EventHandler and CommandHandler methods execute within UnitOfWork
• Associate Commands and Events with streams (explicit and via Aggregates)
• Support processing events and commands in synchronous mode.
• Allow asynchronous command processing by submitting commands to domain
• Add autoflake to pre-commit
• Treat empty string value as None in Date and DateTime Fields
• Support inter-attribute dependencies in Option defaults
• Cache registry, repositories, daos, and models with @cache
• Fix sorting issue with null values in Memory DB
• Add any filter and allow scalar values to in operator in Memory DB