Robotics Service Bus

Connectors use bus in src/transport/spread/*connector.lisp

fixes #2199 fixes #2530

• src/transport/spread/connector.lisp (connector::bus): renamed slot
  connection -> bus
  (connector): added age-limit option
  (initialize-instance :before connector): accept keyword parameter
  bus instead of connection
  (shared-initialize :after connector t): likewise; accept keyword
  parameters tcpnodelay and age-limit; store in configuration
  (notify connector eql t eql :attached): use `ensure-access'
  (notify connector eql t eql :attached): notify bus
  (notify connector scope t): new method; adapter
• src/transport/spread/in-connector.lisp (in-connector): removed
  superclasses `broadcast-processes' and `assembly-mixin'
  (notify in-connector scope eql :attached): subscribe to scope via
  bus
  (notify in-connector scope eql :detached): unsubscribe from scope
  via bus
  (notify in-connector eql t eql :detached): removed; no longer needed
  (receive-notification in-connector t): likewise
  (notification->event in-connector bus-notification t): accept
  `bus-notification' instead of `wire-notification' and thus do not
  deserialize the notification
• src/transport/spread/in-pull-connector.lisp (header): updated
  copyright
  (in-pull-connector::queue): new slot; stores queued events
  (notify in-pull-connector scope eql :attached): removed; no longer
  needed
  (notify in-pull-connector scope eql :detached): likewise
  (handle in-pull-connector bus-notification): new method; push onto
  queue
  (receive-notification in-pull-connector eql nil): new method; try to
  pop from queue
  (receive-notification in-pull-connector eql t): new method; pop from
  queue
• src/transport/spread/in-push-connector.lisp (in-push-connector):
  removed superclasses `threaded-message-receiver-mixin' and
  `error-handling-push-receiver-mixin'; added superclasses
  `broadcast-processor' and `error-policy-mixin'
  (in-push-connector::state): removed; no longer needed
  (apply-error-policy in-push-connector connection-unexpectedly-closed):
  removed; no longer needed
  (apply-error-policy in-push-connector spread-error): likewise
  (notify in-push-connector eql t eql :attached): likewise
  (notify in-push-connector eql t eql :detached): likewise
  (handle in-connector bus-notification): new method; convert to event
  and dispatch
• src/transport/spread/out-connector.lisp
  (event->notification out-connector event): pass notification to bus
  instead of sending
  (event->notification out-connector outgoing-notification): removed;
  handled by `message-sender'
  (send-notification out-connector destined-wire-notification):
  likewise
• src/transport/spread/assembly-mixin.lisp: removed; no longer needed
• test/transport/spread/connectors.lisp (header): updated copyright
  (test case in-connector-root::notification->event): adapted to changes
  (test case define-connector-suite): adapted comment
• rsb-transport-spread.asd (system rsb-transport-spread): removed file
  src/transport/spread/assembly-mixin.lisp