pdqsort vs qsort round 1

;-- use this benchmark: https://github.com/orlp/pdqsort/blob/master/bench/bench.cpp

pdqsort                                     qsort
1000000 shuffled_int  107                   1000000 shuffled_int 277
100 shuffled_int  34                        100 shuffled_int 92
1000000 shuffled_16_values_int  22          1000000 shuffled_16_values_int 43       
100 shuffled_16_values_int  31              100 shuffled_16_values_int 61   
1000000 all_equal_int  1                    1000000 all_equal_int 2
100 all_equal_int  2                        100 all_equal_int 2
1000000 ascending_int  2                    1000000 ascending_int 5
100 ascending_int  3                        100 ascending_int 6
1000000 descending_int  3                   1000000 descending_int 104
100 descending_int  3                       100 descending_int 36
1000000 pipe_organ_int  42                  1000000 pipe_organ_int 349
100 pipe_organ_int  8                       100 pipe_organ_int 44
1000000 push_front_int  3                   1000000 push_front_int 163
100 push_front_int  5                       100 push_front_int 39
1000000 push_middle_int  2                  1000000 push_middle_int 125
100 push_middle_int  3                      100 push_middle_int 32