First round of a task framework. Tasks are job definitions stored in

the database.  They're started with admin/maintenance/start/[task_name]
which sends down some JS/HTML which regularly pings the task at
admin/maintenance/start/[task_id] until its done.

The UI is still very rough.  It works, though!

core/views/admin_maintenance.html.php

@@ -0,0 +1,30 @@
+<? defined("SYSPATH") or die("No direct script access."); ?>
+<div id="gMaintenance">
+  <h1> <?= _("Maintenance Tasks") ?> </h1>
+  <p>
+    <?= _("Occasionally your Gallery will require some maintenance.  Here are some tasks you can run to keep it running smoothly.") ?>
+  </p>
+
+  <div id="gAvailableTasks">
+    <h2> <?= _("Available Tasks") ?> </h2>
+    <table style="width: 400px">
+      <? foreach ($available_tasks as $task) ?>
+      <tr>
+        <td>
+          <?= $task->description ?>
+        </td>
+        <td>
+          <a href="<?= url::site("admin/maintenance/start/$task->name") ?>" class="gDialogLink">
+            <?= _("run") ?>
+          </a>
+        </td>
+      </tr>
+    </table>
+  </div>
+
+  <div id="gRunningTasks">
+    <h2> <?= _("Running Tasks") ?> </h2>
+
+    <i> Task list goes here </i>
+  </div>
+</div>