Prepare for release version 1.5.4

- Update: disable install button for other Plugins if Plugin is already installed

git-svn-id: https://plugins.svn.wordpress.org/footnotes/trunk@1003409 b8457f37-d9ea-0310-8a92-e5e31aec5664

templates/dashboard/other-plugins.html

@@ -11,7 +11,7 @@
         <div class="action-links">
             <ul class="plugin-action-buttons">
                 <li>
-                    <a class="install-now button" href="[[server]]/wp-admin/update.php?action=install-plugin&plugin=[[plugin-name]]&_wpnonce=e7a5c90faf" aria-label="Install [[plugin-title]] now">[[install-label]]</a>
+                    [[install-link]]
                 </li>
                 <li>
                     <a href="[[server]]/wp-admin/plugin-install.php?tab=plugin-information&plugin=[[plugin-name]]&TB_iframe=true&width=600&height=550" class="thickbox" aria-label="More information about [[plugin-title]]" data-title="[[plugin-title]]">[[more-details-label]]</a>