embedded&client library
some fixes: zero at the end of the data added
mysql_list_fields became 'virtual'


include/mysql.h:
  mysql_list_fields became 'virtual'
libmysql/client_settings.h:
  in client library we need proper implementation for list_fields
libmysql/libmysql.c:
  implementation for remote server
libmysqld/lib_sql.cc:
  we still need zero at the end of the data in client (see mysql.cc).
  I feel it should be changed
libmysqld/libmysqld.c:
  implementation for embedded server
sql-common/client.c:
  cli_list_fields member set for client library
sql/client_settings.h:
  we don't need mysql_list_fields in mini_client code