Try to implement VM Ports

* We allow to get only once the stream on VM.stream to avoid leaks.
* The sending without inter-VM synchronization is accomplished
  by pickling the value, adding a task via targetVM.postVMEvent()
  to unpickle the value and bind it in the stream.
* Current result of output of testVM is:
  vm1#(_<optimized>|_<optimized>|!!_)
  instead of
  vm1#(42|wow|!!_)