Decouple state objects from the reactive graph

[dphfox]

Simple state objects are conceptually sensible to imagine as single nodes on the reactive graph. However, for 'compound' state objects made up of multiple independent dependency capturers, such as the For objects, it makes more sense to consider the state object as a collection of reactive nodes.

A new design for Fusion's reactive graph should be created to address these shortcomings in representation so that our internal code is cleaner and easier to follow.