title: Numpy sorting by increasing datetime
body: <p>I have an first array <code>i</code> containing datetime elements (with the shape (33416,)) and a second array <code>m</code> containing floats values (with the shape (33416,20)). This correspong to 20 measurements made at a specific instant.
  I would like to sort <code>i</code> array according to increasing datetime values in <code>i</code> and sort lines of <code>m</code> array accordingly in order to have increasing instant of measurements and its corresponding 20 measurements at this instant.
  Can some help me ? or understand my needs ??? </p>