[3.1.0] Further cleanup, making standalone work again

- Remove includes call in HTMLPurifier.auto.php
- Relax ConfigSchema treatment in generate-includes.php
- Clean up some empty comments (there are probably more)
- De-indent some extends
- class_exists() should now attempt to use autoload
- schema.ser is now a standalone file
- tests/index.php can be run from any directory

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1540 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier.auto.php

@@ -8,6 +8,3 @@
 set_include_path(dirname(__FILE__) . PATH_SEPARATOR . get_include_path() );
 require_once 'HTMLPurifier/Bootstrap.php';
 require_once 'HTMLPurifier.autoload.php';
-
-// This is temporary until we get pure autoload working
-require_once 'HTMLPurifier.includes.php';