RelationsInspector test backend, with transform parent editing

TestBackend2.cs

using UnityEngine;
using UnityEditor;
using System.Collections.Generic;
using System.Linq;
using RelationsInspector;
using RelationsInspector.Backend;

public class TestBackend2 : MinimalBackend<GameObject, string>
{
	public override IEnumerable<Relation<GameObject, string>> GetRelations( GameObject entity )
	{
		// parent -> entity
		if ( entity.transform.parent != null )
			yield return new Relation<GameObject, string>( entity.transform.parent.gameObject, entity, string.Empty );

		// entity -> children
		foreach ( Transform t in entity.transform )
			yield return new Relation<GameObject, string>( entity, t.gameObject, string.Empty );
	}

	public override void OnEntityContextClick( IEnumerable<GameObject> entities, GenericMenu menu )
	{
		menu.AddItem( new GUIContent( "Add as child" ), false, () => api.InitRelation( entities.ToArray() ) );
	}

	public override void CreateRelation( GameObject source, GameObject target)
	{
		Undo.SetTransformParent( target.transform, source.transform, "Adding as child" );
		EditorUtility.SetDirty( source );
		EditorUtility.SetDirty( target );
		api.AddRelation( source, target, string.Empty );
	}

	public override void OnRelationContextClick( Relation<GameObject, string> relation, GenericMenu menu )
	{
		menu.AddItem( new GUIContent( "Un-child" ), false, () => DeleteRelation( relation.Source, relation.Target, relation.Tag ) );
	}

	void DeleteRelation( GameObject source, GameObject target, string tag )
	{
		Undo.SetTransformParent( target.transform, null, "Un-childing" );
		EditorUtility.SetDirty( source );
		EditorUtility.SetDirty( target );
		api.RemoveRelation( source, target, tag );
	}
}