[mdb-dev] minor "dump" improvement

[<kn...@gr...>]

The declaration of buffer_dump in include/mdbtools.h and in dump.c should be
changed to reflect the fact that it is being passed an "unsigned" char*.
This will eliminate a bunch of "ffff"s in the debugging display.

	void buffer_dump(const unsigned char* buf, int start, int end);


-- Karl --