Robotics Service Bus

Support participant hierarchies in src/rsb/**/*.{h,cpp}

fixes #1827

Each Factory::create* method accepts a parent participant as an optional
parameter. If supplied, this parent is passed to the
SignalParticipantCreated and thus available to the introspection
subsystem.

• src/rsb/Factory.{h,cpp} (SignalParticipantCreated): added parent
  parameter
  (Factory::createInformer): added parent participant parameter; pass to
  signalParticipantCreated; extended documentation comment
  (Factory::createListener): similar
  (Factory::createReader): similar
  (Factory::createLocalMethod): similar
  (Factory::createLocalServer): similar
  (Factory::createServer): similar
  (Factory::createRemoteMethod): similar
  (Factory::createRemoteServer): similar
• src/rsb/introspection/Model.{h,cpp} (ParticipantInfo::parentId): new
  member variable; store id of parent participant
  (ParticipantInfo::getParentId): new method; return id of parent
  participant
  (ParticipantInfo::ParticipantInfo): added parentId parameter
• src/rsb/introspection/IntrospectionSender.{h,cpp}
  (IntrospectionSender::addParticipant): added parent participant
  parameter; store its id in the created ParticipantInfo object
  (IntrospectionSender::sendHello):send id of parent participant if any
• src/rsb/introspection/Plugin.cpp (handleParticipantCreated): added
  parent participant parameter; pass to
  IntrospectionSender::addParticipant
• src/rsb/patterns/Server.{h,cpp} (Method): added Handler and
  enable_shared_from_this base classes
  (Method::makeListener): pass shared_ptr to this as parent to
  Factory::createListener
  (Method::makeInformer): similar
• src/rsb/patterns/LocalServer.{h,cpp} (LocalMethod): removed Handler
  and enable_shared_from_this base classes
  (LocalServer): added enable_shared_from_this base class
  (LocalServer::registerMethod): pass shared_ptr to this as parent to
  Factory::createLocalMethod
• src/rsb/patterns/RemoteServer.{h,cpp} (RemoteMethod): removed Handler
  and enable_shared_from_this base classes
  (RemoteServer): added enable_shared_from_this base class
  (RemoteServer::getMethod): pass shared_ptr to this as parent to
  Factory::createRemoteMethod

Reviewed-by: Johannes Wienke <jwienke@techfak.uni-bielefeld.de>