Completed support for http://www.ietf.org/rfc/rfc2396.txt 2.4.3 by adding...

Completed support for http://www.ietf.org/rfc/rfc2396.txt 2.4.3 by adding special case for control code 7F.

Had to increase the bit-vector length to 128, and added #\Rubout (#x7F) to *excluded-characters*.

Added a docstring and test.