and Ndb class description;
Doxyfiles: moved detailed class/member descriptions 
to top of generated files.


ndb/docs/doxygen/Doxyfile.ndbapi:
  Moved detailed class descriptions to top of output.
ndb/docs/doxygen/Doxyfile.ndb:
  Moved detailed class descriptions to top of output.
ndb/docs/doxygen/Doxyfile.odbc:
  Moved detailed class descriptions to top of output.
ndb/docs/doxygen/Doxyfile.test:
  Moved detailed class descriptions to top of output.
ndb/include/ndbapi/Ndb.hpp:
  Documentation edits to Cluster Concepts, 
  Ndb Class Description