1) Fix startTransaction with hint
2) Ship fragment data to API to make better guess
3) Expose both primary & backup replicas 
   To (in the future) be even more clever on choosing nodes for
   transactions/operations


ndb/include/kernel/ndb_limits.h:
  Set maxsize of array with fragment data
ndb/include/kernel/signaldata/DictTabInfo.hpp:
  Send fragment data to API
ndb/src/common/debugger/signaldata/DictTabInfo.cpp:
  Send fragment data to API
ndb/src/kernel/blocks/dbdict/Dbdict.cpp:
  Send fragment data to API
ndb/src/kernel/blocks/dbdict/Dbdict.hpp:
  Send fragment data to API
ndb/src/kernel/blocks/dbdih/DbdihMain.cpp:
  Use Uint16 for fragment info
  Fix uninit variable
ndb/src/ndbapi/Ndb.cpp:
  Impl. startTransaction with hint
ndb/src/ndbapi/NdbDictionaryImpl.cpp:
  Add interface for retreiving replica nodes given a hash-value
ndb/src/ndbapi/NdbDictionaryImpl.hpp:
  Add interface for retreiving replica nodes given a hash-value
ndb/src/ndbapi/ndb_cluster_connection.cpp:
  remove Fragment2NodeMap and put it on table instead
ndb/src/ndbapi/ndb_cluster_connection_impl.hpp:
  remove Fragment2NodeMap and put it on table instead
ndb/test/ndbapi/testNdbApi.cpp:
  Test some more