o Fix typo in compiler macro for sub-d-qd

qd.lisp:
o Use 3-arg versions in div-qd-t to speed things up.  Approximately
  doubles the speed with clisp.

qd-fun.lisp:
o Use 3-arg versions in sqrt-qd to speed things up.  Approximately
  doubles the speed with clisp.

  sub-d-qd, and neg-qd.
o Correct the compiler macros for CMUCL for sub-qd and sqr-qd.

o Add compiler macro for SQR-QD.

o Declare add-qd-t, mul-qd-t and div-qd-t as inline functions so that
  everything is still fast on cmucl.

consing by allowing the third argument to be a place where the result
can be stored.  This is intended to help reduce allocation and gc
costs for Lisps that use arrays to represent quad-doubles.

More work is needed to make the compiler macros do the right thing for
CMUCL.

qd-rep.lisp:
o Add %STORE-QD-D to store a quad-double into a place.  For CMUCL,
  there place argument is ignored and a fresh quad-double is created.

qd.lisp:
o Modify ADD-QD, SUB-QD, MUL-QD, and DIV-QD to take an optional third
  argument indicating where the result can be stored.   Ignored on
  CMUCL.
o Add ADD-QD-T, SUB-QD-T, MUL-QD-T, and DIV-QD-T, which are 3-arg
  functions with the third arg always required which is the storage
  area to hold the result.  Ignored on CMUCL.
o Add compiler macros to convert ADD-QD and friends to ADD-QD-T if the
  third arg is always given.  The effect is, essentially, inlining
  ADD-QD.

o Remove extra rem-pi/2-int.

qd-rep.lisp:
o Fix typo in float-infinity-p for Allegro.
o Ignore var in float-infinity-p and friends.

  float-trapping-nan-p.  These return NIL by default, unless the Lisp
  implementation has a suitable version.
o Remove CMU conditionalization for float-infinity-p, float-nan-p,
  float-trapping-nan-p.

qd-fun.lisp:
o Comment out the old sin/cos routines
o Fix a few mistakes in accurate-sincos-qd
o Rename accurate-sincos-qd to sincos-qd.

o Add macro WITH-QD-PARTS to extract the components of a quad-double.

qd.lisp:
o Use the macro as needed.

all Lisps.

a portable presentation using a (simple-array double-float (4)) to
hold a %quad-double number.

All of the tests pass with the portable representation.

qd.lisp:
o Moved representation to qd-rep.lisp.
o INTEGER-DECODE-QD was dependent on the internal representation.
  Replace with a function using the appropriate accessors.

qd.system:
o Add new file qd-rep.lisp.

qd-rep.lisp:
o Representation moved here.
o Add portable implementation using a simple-array for holding a
  %quad-double.