add unread_first view mode

include/functions.php

@@ -2407,6 +2407,10 @@
 				$order_by = "score DESC, $order_by";
 			}
 
+			if ($view_mode == "unread_first") {
+				if (!$override_order) $override_order = "unread DESC, $order_by";
+			}
+
 			if ($override_order) {
 				$order_by = $override_order;
 			}

index.php

@@ -160,6 +160,7 @@
 			<option value="marked"><?php echo __('Starred') ?></option>
 			<option value="published"><?php echo __('Published') ?></option>
 			<option value="unread"><?php echo __('Unread') ?></option>
+			<option value="unread_first"><?php echo __('Unread First') ?></option>
 			<!-- <option value="noscores"><?php echo __('Ignore Scoring') ?></option> -->
 		</select>