Add link to home page (fixes #1993, fixes #1999)

gui/index.html

@@ -462,6 +462,7 @@
   <nav class="navbar navbar-default navbar-fixed-bottom">
     <div class="container">
       <ul class="nav navbar-nav">
+        <li><a class="navbar-link" href="http://syncthing.net/" target="_blank"><span class="glyphicon glyphicon-home"></span>&nbsp;<span translate>Home page</span></a></li>
         <li><a class="navbar-link" href="http://docs.syncthing.net/" target="_blank"><span class="glyphicon glyphicon-book"></span>&nbsp;<span translate>Documentation</span></a></li>
         <li><a class="navbar-link" href="https://forum.syncthing.net" target="_blank"><span class="glyphicon glyphicon-question-sign"></span>&nbsp;<span translate>Support</span></a></li>
         <li><a class="navbar-link" href="https://github.com/syncthing/syncthing/releases" target="_blank"><span class="glyphicon glyphicon-info-sign"></span>&nbsp;<span translate>Changelog</span></a></li>