Fix for tickets 1009 and 603: Show a themed error page to guests / registered users (not to admins though). And show a login form to guests for 404 (incl. insufficient view permissions) errors.

modules/gallery/views/error.html.php

@@ -0,0 +1,12 @@
+<?php defined("SYSPATH") or die("No direct script access.") ?>
+<div id="g-error">
+  <h1>
+    <?= t("Dang...  Something went wrong!") ?>
+  </h1>
+  <h2>
+    <?= t("We tried really hard, but it's broken.") ?>
+  </h2>
+  <p>
+    <?= t("Talk to your Gallery administrator for help fixing this!") ?>
+  </p>
+</div>