Allow page switching with arrow keys

Fixes #2

templates/partials/list.html.nunjucks

@@ -81,6 +81,11 @@
       $(window).resize(onresize);
       $(document).load(onresize);
       $(document).ready(onresize);
+      $(document).keypress(function(e) {
+        if($("#search-overlay").hasClass("shown")) return;
+        if(e.key == "ArrowRight") window.location = "{{config.baseurl}}/{{metadata.nexturl}}";
+        if(e.key == "ArrowLeft") window.location = "{{config.baseurl}}/{{metadata.prevurl}}";
+      });
     })(jQuery);
     </script>
 </div> <!-- #content -->