Robotics Service Bus

• src/rsb/Event.{h,cpp}: changed Event::id into a pointer which is not
  set initially, but computed lazily; added Event::sequenceNumber
• src/rsb/Informer.h: set event sequence number in
  Informer::checkedPublish; added sequence number counter WHICH IS NOT
  YET THREAD-SAFE
• src/rsb/transport/spread/Assembly.{h,cpp}: use sequence numbers
  instead of ids to identify corresponding events of notifications
• src/rsb/transport/spread/OutConnector.cpp: store event sequence
  number instead of id in notification
• src/rsb/transport/spread/ReceiverTask.cpp: extract event sequence
  number instead of id from notification
• test/rsb/transport/spread/AssemblyTest.cpp: adapted created of mock
  notifications

• RSBProtocol/Protocol.proto: moved MetaData.sender_id to
  Notification.sender_id; sequence_number and sender_id uniquely
  identify the event; both are still available even if
  Notification.meta_data is omitted (this is relevant for fragmented
  events)

• src/rsb/transport/spread/Assembly.{h,cpp}: use the concatenation of
  sender id and event sequence number as unique event identifier

• src/event.lisp (event): removed superclass uuid-mixin; updated
  documentation
  (event::sequence-number): new slot; stores a sequence number
  (event::id): made writer private; allow nil value; added
  documentation
  (shared-initialize :after event t): invalid stored id
  (event-id :before event): compute event id by calling
  `%maybe-set-event-id'
  (setf event-sequence-number :after t event): new method; invalidate
  stored id
  (setf event-origin :after t event): likewise
  (event=): changed keyword parameter compare-id? ->
  compare-sequence-numbers?
  (print-object event t): call `%maybe-set-event-id' to force id
  computation if necessary
  (%maybe-set-event-id): new function; helper function to compute
  event id based on origin id and sequence number
• src/informer.lisp (informer::sequence-number-generator): new slot;
  stores a sequence number generation function
  (send informer event): call the sequence number generator and store
  the resulting sequence number in the event
• src/transport/spread/conversion.lisp (one-notification->event):
  extract the sequence number instead of the id from the notification
  (event->notifications): store the sequence number instead of the id
  (make-notification): likewise
• cl-rsb.asd (system cl-rsb): added dependency of src/event.lisp on
  src/types.lisp

• src/transport/spread/fragmentation.lisp (assembly::id): changed type
  octet-vector -> sequence-number
  (print-object assembly t): print id as sequence number rather than
  partial UUID
  (ensure-assembly assembly-pool integer integer): changed specializer
  simple-array -> integer
  (merge-fragment assembly-pool t): identify the notification using
  `notification-sequence-number'; `notification-id' has been removed

• src/transport/spread/conversion.lisp (one-notification->event):
  obtain sender id from notification instance rather than contained
  meta-data instance
  (make-notification): store sender id in notification instance rather
  than contained meta-data instance

• test/event.lisp (test event-root::id-computation): new test case;
  check computation of event ids based on sender ids and sequence
  numbers

• src/transport/spread/fragmentation.lisp (assembly::id): changed type
  sequence-number -> simple-array
  (print-object assembly t): print parts of the sender id and the
  complete sequence number
  (ensure-assembly assembly-pool simple-array integer): changed
  specializer integer -> simple-array
  (merge-fragment assembly-pool t): use `%make-key' to compute
  suitable keys for identifying notifications
  (%make-key): new function; compute a notification key from a
  sequence number and a sender id

Support for name-based UUIDs according to Version 5 specifcation for EventIds (this fixes #421).
Id class refactored to EventId
Added UUIDTools class for UUID related helper functions.
Removed ControversialRules from PMD ruleset.