Adding a new behavior for the doctrine engine.
Add a new entity manager.

This will be used for tracking the entities of any model,
regardless of where it came from.
Add the new entity manager to the metadata.
Fixing typoe.
Cleaning up the doctrine initializer.
Adding tests for the Repo.
Adding the Forwardable behavior.
Updating the Doctrine Repo to use Metadata.
Fixing the UnknownModel error signature.
Update dependencies.
Add build method for creating new instances of the class.

Also, calling __construct() before attaching members so Pimple
can fully construct itself.
Removing the build factory for now.
Removing the engine.

Watching everything break.
Removing the Drivable trait.
Removing the engine from the Metadata.
Add a populator for Doctrine types.
Properly map types with doctrine.
Update the result to take a manager.
Remove unnecessary relate() method.
Remove outdated MapperInterface.