ndb/include/kernel/ndb_limits.h:
  #define for max null bits
ndb/include/kernel/signaldata/TupFrag.hpp:
  Error code for too many nullbits
ndb/include/util/Bitmask.hpp:
  Cosmetic fix
ndb/src/common/util/Bitmask.cpp:
  handle (pos % 32) == 0
  more unit tests
ndb/src/kernel/blocks/dbtup/DbtupMeta.cpp:
  Check bitmask overflow
ndb/src/ndbapi/ndberror.c:
  New error code
ndb/test/ndbapi/testBitfield.cpp:
  Update test program
ndb/test/run-test/daily-basic-tests.txt:
  Add testBitfield to autotest