parallel quicksort in pthread

time ./00_quicksort_parallel02.exe 0
real	0m23.912s
user	0m23.859s
sys	0m0.061s




time ./00_quicksort_parallel02.exe 2
real	0m13.665s
user	0m23.781s
sys	0m0.0461s




time ./00_quicksort_parallel02.exe 4
real	0m7.551s
user	0m27.921s
sys	0m0.046s




time ./00_quicksort_parallel02.exe 8
real	0m6.457s
user	0m32.796s
sys	0m0.265s