Function proxy

docs/app/js/sanddance-app.js:149525–149530

(op)

        return op;
    },
    proxy (op) {
        const vref = op instanceof Entry ? ref(op) : op;
        return this.add(Proxy({
            value: vref
        }));
    },
    addStream (stream) {
        this.streams.push(stream);
        stream.id = this.id();