Revise max() and min() to comply with the 8/2/2004 update to the specification

Revise max() and min() to comply with the 8/2/2004 update to the specification
(version 1.45):

The max and min operations follow the rules in the current IEEE 754 revision draft:
if one operand is a quiet NaN and the other is number, then the number is always returned
if both operands are finite and equal in numerical value then an ordering is applied:
    if the signs differ then max returns the operand with the positive sign and
    min returns the operand with the negative sign; if the signs are the same then
    the exponent is used to select the result.