Function get_proper_divisors 

pub fn get_proper_divisors(number: u64) -> Vec<u64>

Returns the proper divisors of the given number n.

Proper divisors: numbers less than n which divide evenly into n.

Examples

let number = 28;
let answer = jabba_lib::jmath::get_proper_divisors(number);

assert_eq!(answer, vec![1, 2, 4, 7, 14]);