Clean up printing and fix printing bug in non-cmucl.

Clisp was printing #q(1 2) as #q(#q#q1 #q#q2).  This is caused by
PRINT-OBJECT for QD-COMPLEX printing a #q in addition to a #q printed
by QD-FORMAT.

qd-class.lisp:
o Use the same PRINT-OBJECT method for qd-real for all Lisps.
o Remove extraneous #q from PRINT-OBJECT method for qd-complex.

qd-io.lisp:
o QD-FORMAT for cmucl needs to output #q.