Is fast_best_order_sort intended to be usable by NonDominatedSorting?

[JonathanRaynerMonumo]

#495 has some benchmarks that seem to show good speed for fast_best_order_sort from the cython code, but it doesn't seem to be importable here.

[blankjul]

I can't recall if there was a reason to make it not accessable. Maybe I wanted to wait until my co-workers paper was officially available.

Please see my commit above and give it a test if this works now.

import numpy as np

from pymoo.util.nds.non_dominated_sorting import NonDominatedSorting

np.random.seed(1)
F = np.random.random(size=(100, 2))

nds = NonDominatedSorting(method='fast_best_order_sort')

res = nds.do(F)
print(res)