Don't print APRCL progress in quite mode

Kruoli asked the extra output could be hidden in quiet mode which seems a reasonable request.

Currently progress wouldn't be printed for numbers up to 400 digits (that take <4 seconds) and would be printed for numbers up to 499 digits (<11 seconds) This change would mean that for old computers you might find a factor but it would take up to an additional ~30 second with no output which seems very reasonable.

time echo "10090030271*(10^400+69)" | ./ecm -param 0 -sigma 3923937547 1e3 1e6;
time echo "10090030271*(10^499-1259)" | ./ecm -param 0 -sigma 3923937547 1e3 1e6;