Start sketching ideas for query implementation.
Branch sketching: Query as entity; Query as transformation of Entity; Query wrapping Entity (variation on Component style)
Feel out how binding the wrapper Query callback to space feels.
Wrapped Query style now has callback hooks for key collision phases.
Only create one collision handler instance and collision type for all queries.
Improve documentation of wrapping Query style sketch.
Start real Query implementation based on wrapper style.
Update documentation a bit.
Restructure objects stored in Space (separate collection for entities, constraints, and queries)
Sketch ideas on how constraints and queries should be serialized.
Store filename for entity serialization in a constant (editable in one place, not two)
Pass conversion tables (entity <=> id)  to load / dump methods.
All load / dump code for all list types is the same. Defer handling of differences to pack / unpack.
Query binding should effect the visual style.
Place Query class in a module for easy programatic constant lookup.
Restore last known style mode when mouse hover event ends.
Make sure all List types in Space add and delete at least to a basic extent.
Move basic List #add / #delete implementation into List to reduce duplication.
Specify that different List types should look in different modules for class constants.
Space requires knowing the constraints / queries modules. So, stub Constraints module, and load constraints and queries before Space.