Make PP to find it's way through complex nested transitions

[edjafarov]

if there is client-server, server-worker1, server-worker2

than if pipe need to get worker1-worker2, it should resolve back to worker1-server and then go into server-worker2

upd: Workers probably do not know about capabilities of other envs thus probably one should define PromisePipe.envTransitions[worker1][worker2] = "server"