HTML export: before showing the dive list, sort descending by dive number

This way the newest dive gets shown first (which I think makes much more
sense) and the dives are in order as we show them in Subsurface.

I actually think we should toggle trips on by default - but I'm not sure.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

theme/list_lib.js

@@ -20,6 +20,7 @@ function showAllDives()
 	for (var i = 0; i < items.length; i++) {
 		itemsToShow.push(i);
 	}
+	change_sort_col('1');
 	olditemstoshow = itemsToShow;
 	start = 0;
 	viewInPage();