Core and Default plugins separated, now loads on install

_flow_ reported on IRC that install.php had stopped working. This was
because default plugins had been put into two separate lists, and the
list with AuthCrypt was never loaded when performing an installation.

Core plugins cannot be disabled.

I also removed the Memcache autodetection thing since it should be
solved in a more elegant manner.

lib/default.php

@@ -20,17 +20,17 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  * @category  Config
- * @package   StatusNet
+ * @package   GNUsocial
  * @author    Evan Prodromou <evan@status.net>
  * @copyright 2008-9 StatusNet, Inc.
  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
- * @link      http://status.net/
+ * @link      http://www.gnu.org/software/social/
  */
 
 $default =
     array('site' =>
-        array('name' => 'Just another StatusNet microblog',
-              'nickname' => 'statusnet',
+        array('name' => 'Just another GNU social node',
+              'nickname' => 'gnusocial',
               'wildcard' => null,
               'server' => $_server,
               'theme' => 'neo',
@@ -305,19 +305,22 @@ $default =
         'logincommand' =>
         array('disabled' => true),
         'plugins' =>
-        array('default' => array('Geonames' => null,
-                                 'ClientSideShorten' => null,
-                                 'StrictTransportSecurity' => null,
-                                 'Bookmark' => null,
-                                 'Event' => null,
-                                 'Poll' => null,
-                                 'QnA' => null,
-                                 'SearchSub' => null,
-                                 'TagSub' => null,
-                                 'OpenID' => null,
-                                 'Directory' => null,
-                                 'ExtendedProfile' => null,
-                                 'Activity' => null),
+        array('core' => array(
+                            'AuthCrypt' => null,
+                            'LRDD' => null,
+                            'StrictTransportSecurity' => null,
+                        ),
+              'default' => array(
+                            'Activity' => null,
+                            'Bookmark' => null,
+                            'ClientSideShorten' => null,
+                            'Event' => null,
+                            'OpenID' => null,
+                            'Poll' => null,
+                            'QnA' => null,
+                            'SearchSub' => null,
+                            'TagSub' => null,
+                        ),
               'locale_path' => false, // Set to a path to use *instead of* each plugin's own locale subdirectories
               'server' => null,
               'sslserver' => null,