~raph/immutable

More development of proxy objects
Start of proxy objects

Allow mutation of values, actually producing deltas.
Switch to reference-counted subtrees
Some more plumbing

Not any particular result, but broadcasts events to receivers.
Start basics of wiring up UI

Still very much a sketch, but there's application state that accepts
deltas and applies them.
Initial commit of prototype

A dynamic data structure hopefully useful for reactive-style UI.