Release 3.3: DB->get_byteswapped

The DB->get_byteswapped() method method can return an error in the Berkeley DB 3.3 release, and so requires an interface change. C and C++ applications calling DB->get_byteswapped() should be changed to treat the method's return as an error code, and to pass an additional second argument of type int * to the method. The additional argument is used as a memory location in which to store the requested information.