Fix some hackificator odds and ends in wp-admin:

* `wp-activate.php` and `wp-admin/themes.php` don't need the closing PHP tag
* Switch single quotes for HTML attribute values to double in a few places
* Convert `include_once file.php` syntax to `include_once( 'file.php' )`
* Add access modifiers to methods/members in: `_WP_List_Table_Compat`, `Walker_Nav_Menu_Edit`, `Walker_Nav_Menu_Checklist`, `WP_Screen`, `Walker_Category_Checklist`
* `edit_user()` doesn't need to import the `$wpdb` global
* `wp_list_widgets()` doesn't need to import the `$sidebars_widgets` global
* switch/endswitch syntax is not supported in Hack
* A `<ul>` in `wp-admin/users.php` is unclosed

See #27881.


git-svn-id: https://develop.svn.wordpress.org/trunk@28500 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/options.php

@@ -204,7 +204,7 @@ include( ABSPATH . 'wp-admin/admin-header.php' ); ?>
   <form name="form" action="options.php" method="post" id="all-options">
   <?php wp_nonce_field('options-options') ?>
   <input type="hidden" name="action" value="update" />
-  <input type='hidden' name='option_page' value='options' />
+  <input type="hidden" name="option_page" value="options" />
   <table class="form-table">
 <?php
 $options = $wpdb->get_results( "SELECT * FROM $wpdb->options ORDER BY option_name" );