normalizeColumns

import mir.ndslice;
import mir.math;

auto data = mininitRcslice!double(2,2);
data[] = [[ 2, -1],
          [-2,  1]];
//sd1 = 2 * sqrt(2.0);
//sd2 = sqrt(2.0);
auto x = 1.0 / sqrt(2.0);
auto scaled = mininitRcslice!double(2,2);
scaled[] = [[ x, -x],
            [-x,  x]];
auto stdDev = mininitRcslice!double(2);
assert(normalizeColumns(data, stdDev) == scaled);
assert(stdDev == [2*sqrt(2.0), sqrt(2.0)]);