Use local_time gem for timezone replacement (#2174)

For the 'time ago' value of stream entry simple statuses and the timestamp value
of detailed statuses - output their UTC value and use the browser timezone to
convert locally.

app/assets/javascripts/application_public.js

@@ -2,6 +2,7 @@
 //= require jquery_ujs
 //= require extras
 //= require best_in_place
+//= require local_time
 
 $(function () {
   $(".best_in_place").best_in_place();