Display "secs", "mins", "hrs" when n > 1

When dealing with more than one second, minute or hour display secs,
mins or hrs instead of sec, min or hr.

In the case of secs it's always more than 1.

h/static/scripts/test/time-test.js

@@ -11,11 +11,11 @@ var year = day * 365;
 var FIXTURES_TO_FUZZY_STRING = [
   [10, 'Just now'],
   [29, 'Just now'],
-  [49, '49 sec'],
+  [49, '49 secs'],
   [minute + 5, '1 min'],
-  [3 * minute + 5, '3 min'],
+  [3 * minute + 5, '3 mins'],
   [hour, '1 hr'],
-  [4 * hour, '4 hr'],
+  [4 * hour, '4 hrs'],
   [27 * hour, '1 Jan'],
   [3 * day + 30 * minute, '1 Jan'],
   [6 * month + 2 * day, '1 Jan'],

h/static/scripts/time.js

@@ -28,15 +28,29 @@ function delta(date, now) {
 }
 
 function nSec(date, now) {
-  return '{} sec'.replace('{}', Math.floor(delta(date, now)));
+  return '{} secs'.replace('{}', Math.floor(delta(date, now)));
 }
 
 function nMin(date, now) {
-  return '{} min'.replace('{}', Math.floor(delta(date, now) / minute));
+  var n = Math.floor(delta(date, now) / minute);
+  var template = '{} min';
+
+  if (n > 1) {
+    template = template + 's';
+  }
+
+  return template.replace('{}', n);
 }
 
 function nHr(date, now) {
-  return '{} hr'.replace('{}', Math.floor(delta(date, now) / hour));
+  var n = Math.floor(delta(date, now) / hour);
+  var template = '{} hr';
+
+  if (n > 1) {
+    template = template + 's';
+  }
+
+  return template.replace('{}', n);
 }
 
 // Cached DateTimeFormat instances,