* because it is not referentially transparent; normally we reserved parens for
side-effecting code but given how people thoughtlessly close over it we revised
that that decision for sender
* caller can still omit parens
- removed retry-window and related settings
- removed gate-invalid-addresses-for
- gate is now mandatory
- remoting has a dedicated dispatcher by default
- updated tests to work with changed timings
- added doc section for association lifecycle
* When actor system was restarted quickly the new system replied to
heartbeats and Terminated was never triggered for actors in old
system.
* Solved by sending an extra Watch system message when first hearbeat
is received for an address and when a change of system uid is detected.
