Helper for creating circular proxy for cycle.js
const foo = Foo({value$: bar.value$, DOM})
const bar = Bar({HTTP, prop$: foo.prop$})
import proxy from 'cycle-circular/rx'
...
const value$ = proxy()
const foo = Foo({value$, DOM})
const bar = Bar({HTTP, prop$: foo.prop$})
bar.value$.let(value$.proxy)
.subscribe(...)
npm i cycle-circular @cycle/rx-adapter -S