Fix #784 ordering in page collections

Fixes accentuated characters ordering and also uppercase letters being
put first.

Re-done implementation made in
fc5302f
6a817ed but reverted in
894142d
6167ae2 due to extension not checked

system/src/Grav/Common/Page/Pages.php

@@ -1060,7 +1060,12 @@ protected function buildSort($path, array $pages, $order_by = 'default', $manual
             $list = $this->arrayShuffle($list);
         } else {
             // else just sort the list according to specified key
-            asort($list, $sort_flags);
+            if (extension_loaded('intl')) {
+                $col = new \Collator(setlocale(LC_COLLATE, 0)); //`setlocale` with a 0 param returns the current locale set
+                $col->asort($list, $sort_flags);
+            } else {
+                asort($list, $sort_flags);
+            }
         }