MDL-39854 reimplement Frankenstyle support and enable classloader

Better performance, more reliable, completely self contained,
more validation and full backwards compatibility.

This will also allow us to implement ignoring of plugins.

lib/setup.php

@@ -289,6 +289,8 @@ umask(0000);
 $CFG->yui2version = '2.9.0';
 $CFG->yui3version = '3.9.1';
 
+// core_component can be used in any scripts, it does not need anything else.
+require_once($CFG->libdir .'/classes/component.php');
 
 // special support for highly optimised scripts that do not need libraries and DB connection
 if (defined('ABORT_AFTER_CONFIG')) {
@@ -504,6 +506,13 @@ ini_set('include_path', $CFG->libdir.'/pear' . PATH_SEPARATOR . ini_get('include
 //please note zend library is supposed to be used only from web service protocol classes, it may be removed in future
 ini_set('include_path', $CFG->libdir.'/zend' . PATH_SEPARATOR . ini_get('include_path'));
 
+// Register our classloader, in theory somebody might want to replace it to load other hacked core classes.
+if (defined('COMPONENT_CLASSLOADER')) {
+    spl_autoload_register(COMPONENT_CLASSLOADER);
+} else {
+    spl_autoload_register('core_component::classloader');
+}
+
 // Load up standard libraries
 require_once($CFG->libdir .'/textlib.class.php');   // Functions to handle multibyte strings
 require_once($CFG->libdir .'/filterlib.php');       // Functions for filtering test as it is output