Correct and nicely format the date ranges for pages.

An endash is appropriate typographically for ranges.
The subquery ensures the LIMIT/OFFSET is respected in the min/max.
And now I'm using the system time format.

data/pages/history

@@ -36,10 +36,11 @@ and to visually communicate the paths surfers took through this history. #}
     {% each-row %}
       {% for i in num_pages %}
         {% if i != url.query.page %}<a href="odysseus:history?page={{i}}"{% else %}<strong {% endif %}
-          {% query %}SELECT min(visited_at) AS earliest, max(visited_at) AS latest FROM page_visit
-                  LIMIT {{pagesize}} OFFSET {{i}}*{{pagesize}};
+          {% query %}SELECT min(visited_at) AS earliest, max(visited_at) AS latest
+                FROM (SELECT visited_at FROM page_visit
+                  ORDER BY visited_at DESC LIMIT {{pagesize}} OFFSET {{i}}*{{pagesize}});
           {% each-row %}
-            title="{{latest}} - {{earliest}}"
+            title="{{latest|date}}–{{earliest|date}}"
           {% endquery %}
         >●</{% if i != url.query.page %}a{% else %}span{% endif %}>
       {% empty %}

src/Services/Prosody/lib.vala

@@ -676,7 +676,10 @@ namespace Odysseus.Templating.Std {
     private class DateFilter : Filter {
         public override Data.Data filter(Data.Data date, Data.Data format) {
             var datetime = new DateTime.from_unix_local(date.to_int());
-            var ret = datetime.format(format.to_string());
+            var format_str = format.to_string();
+            if (format_str == "")
+                format_str = @"$(Granite.DateTime.get_default_date_format()) $(Granite.DateTime.get_default_time_format())";
+            var ret = datetime.format(format_str);
             return new Data.Literal(ret);
         }
     }