basiliscos / cpp-rotor

• [improvement] more modern cmake usage

• [improvement] registy actor was added to allow via name/address runtime
  matching do services discovery
• [improvement, breaking] minor changes in supervisor behavior: now it
  is considered initialied when all its children confirmed initialization
• [improvement] supervisor_policy_t was introduced to control supervisor
  behavior on a child-actor startup failure
• [example] examples/ev/pong-registry.cpp how to use registry
• [doc] patterns/Registry was added

• [improvement] response can be inherited from rotor::arc_base, to allow
  forwarding requests without copying it (i.e. just intrusive pointer is created)
• [example] examples/boost-asio/beast-scrapper.cpp has been added; it
  demonstrates an app with pool of actor workers with request-response forwarding

• [improvement] the [request-response] approach is integrated to support basic
  [reliable] messaging: response notification failure will be delivered,
  if the expected response will not arrive in-time
• [improvement] lambda subscribiers are supported
• [improvement] actor behavior has been introduced to offload actor's
  interface
• [breaking] supervisor is constructed with help of supervisor_config_t,
  which contains shutdown timeout value
• [breaking] supervisor does not spawns timeout timer for overall shutdown
  procedure, instead per-child timers are spawned. The root supervisor
  the same way monitors child-supervisor shut down
• [breaking] supervisor create_actor method now takes child max
  init time value. If it does not confirm, the child actor will be asked
  for shut down.
• [breaking] shutdown request sent to an child actor now timeout-tracked
  by supervisor. The message type has changed to message::shutdown_request_t
• [breaking] init request sent to an child actor now timeout-tracked
  by supervisor. The message type has changed to message::init_request_t
• [breaking] actor's state request message type now message::state_request_t,
  which follows the generic request/response pattern. The response type
  is now message::state_response_t.
• [breaking] {asio, ev, ws} supervisor configs are renamed to have
  corresponding suffix.

• [improvement] locality notion was introduced, which led to possibilty
  to build superving trees, see [superving-trees]]
• [breaking] the outbound field in rotor::supervisor_t was renamed just to queue
• [breaking] rotor::address_t now contains const void* locality
• [breaking] rotor::asio::supervisor_config_t now contains
  std::shared_ptr to strand, instead of creating private strand
  for each supervisor
• [bugfix] redundant do_start() method in rotor::supervisor_t was
  removed, since supervisor now is able to start self after compliting
  initialization.
• [bugfix] rotor::supervisor_t sends initialize_actor_t to self
  to advance own state to INITIALIZED via common actor mechanism,
  instead of changeing state directly on early initialization phase
  (do_initialize)
• [bugfix] rotor::asio::forwarder_t now more correctly dispatches
  boost::asio events to actor methods
• [bugfix] rotor::ev::supervisor_ev_t properly handles refcounter

add libev support