Clever sort

[davorg]

Add a sort method that handles the Succession to the Crown Act.

Pseudocode:

if ($a->gender ne $b->gender) {
  if ($a->gender eq 'm') {
    if ($a->born < '28 October 2011') {
      return -1;
    } else {
      return $a->born <=> $b->born;
    }
  } else {
    if ($b->born < '28 October 2011') {
      return 1;
    } else {
      return $a->born <=> $b->born;
    }
  }
} else {
   return $a->born <=> $b->born;
}

Should probably be a method on the person resultset.