Extend number_set interface

Extend number_set interface

* number_set.h (number_set_array_is_empty, is_number_in_set_array,
add_number_to_set_array, clear_number_set_array,
invert_number_set_array, alloc_number_set_array, free_number_set_array):
New function prototypes.
* number_set.c (number_set_array_is_empty, is_number_in_set_array,
add_number_to_set_array, clear_number_set_array,
invert_number_set_array, alloc_number_set_array, free_number_set_array):
New functions.
* basic_filters.c (qualify_syscall_number, qualify_syscall_regex,
qualify_syscall_class, qualify_syscall_name): Use
add_number_to_set_array.
(qualify_syscall_tokens, qualify_tokens): Use
clear_number_set_array and invert_number_set_array.
* filter_qualify.c (qualify_inject_common): Use alloc_number_set_array,
number_set_array_is_empty, is_number_in_set_array,
add_number_to_set_array, and free_number_set_array.
(qual_flags): Use is_number_in_set_array.