Added id tests. Can't run them yet (have to fix compilation of backend).
Implemented event dispatching but not finished yet.
Added tests and fixes for event dispatcher.
Renamed event publishing function in event dispatcher.
Added association of event publishing/observation with a specific id.
Fixed id values not being usable into concurrent container because of hashing stuffs.
Fixed id hashing function for tbb which shouldn't be an overloading.
backend: Event publication/observation can now be associated to a specific emitting source id.