Function kendalls::tau_b_with_comparator

pub fn tau_b_with_comparator<T, F>(
    x: &[T], 
    y: &[T], 
    comparator: F
) -> Result<f64, Error> where
    T: PartialOrd + Clone + Default,
    F: FnMut(&T, &T) -> Ordering, 

The same as tau_b but also allow to specify custom comparator for numbers for which Ord trait is not defined.