Added option to switch themes.

Added standalone pages for:
 - Exhibitions
 - Events
 - Institutions
 - Collections
Added option to limit display to only a given set of institutions.

object.php

@@ -28,6 +28,11 @@ if (!$contents || (isset($contents[0]) and $contents[0] == "There is no object w
     return;
 }
 
+if ($settings['limitToInstitutions'] != [] and !in_array($contents['object_institution']['institution_id'], $settings['limitToInstitutions'])) {
+    echo printErrorPage("This object does not belong to an enabled institution.");
+    return;
+}
+
 /*
  * Output
  */