v0.0.9

• API simplification: From an observable setter & a setFields method to updated nested fields, it's now collapsed into one update method for updating the observable state
• As such, Observables don't use getters and setters anymore (which may be hard to track as applications scale). Instead, we now use .value to get the state and .update(updateFn(val)) to set state
• Subscriptions are now more intuitive via the `this.prop = this.subscribe(store, prop) syntax.