+ some more docs on event


ndb/examples/ndbapi_event_example/ndbapi_event.cpp:
  ndbapi event code cleanup
ndb/include/kernel/signaldata/CreateEvnt.hpp:
  ndbapi event code cleanup
ndb/include/ndbapi/NdbDictionary.hpp:
  ndbapi event code cleanup
ndb/src/ndbapi/NdbDictionaryImpl.cpp:
  ndbapi event code cleanup
ndb/src/ndbapi/ndberror.c:
  ndbapi event code cleanup