TransferChannel is no longer Selectable. Doesn't really work w/o locks

tryReceives don't wait for trySends and vice-versa -> live-lock
An empty skeleton of what may become a futer selectable transfer channel
Made TransferChannel a ReceiveSelector only

Can be either ReceiveSelector or SendSelector, but not both
Channels overhaul
Cont channel overhaul
Parent interface check resulted in false negatives in is suspendible because of isJavaCore
Fixed TransferChannel-Selector deadlock