Add 'online' value for Mustache template

Provide an 'online' value to the Search Result Mustache template. This will, for example, allow you to put things in your Search Result template that will show up when your site is displayed live (PHP), but will not be output when your site is displayed using the offline Javascript, and vice versa.

eg.
{{#online}}
  This will only display in your template if it's online.
{{/online}}
{{^online}}
  This will only display in your template it it's offline.
{{/online}}

orcinus/js/template.offline.js

@@ -80,8 +80,12 @@ function os_return_all() {
 
 // Create the Mustache template
 let os_TEMPLATE = {
+  errors: false,
+
+  online: false,
   version: '{{version}}',
   searchable: false,
+
   addError: function(text) {
     if (!this.errors) {
       this.errors = {};

orcinus/search.php

@@ -59,6 +59,8 @@ foreach ($_RDATA['s_latin'] as $char => $latin) {
 // {{{{{ Initialize the Mustache templating engine
 class OS_Mustache {
   public $errors;
+
+  public $online = true;
   public $version;
   public $searchable;