Change the way that we track modules.

Each module now has a "module.info" file that has information about
the module, including the core.  We can display the installed version,
and the version in the code.

Also take a first shot at a modules admin page.

core/views/admin_modules.html.php

@@ -0,0 +1,19 @@
+<? defined("SYSPATH") or die("No direct script access."); ?>
+<div id="gModules">
+  <table>
+    <tr>
+      <th> <?= _("Installed") ?> </th>
+      <th> <?= _("Name") ?> </th>
+      <th> <?= _("Version") ?> </th>
+      <th> <?= _("Description") ?> </th>
+    </tr>
+    <? foreach ($available as $module_name => $module_info):  ?>
+    <tr>
+      <td> <?= form::checkbox($module_name, '', module::is_installed($module_name)) ?> </td>
+      <td> <?= _($module_info["name"]) ?> </td>
+      <td> <?= module::get_version($module_name) ?> </td>
+      <td> <?= _($module_info["description"]) ?> </td>
+    </tr>
+    <? endforeach ?>
+  </table>
+</div>