[3.1.0] Implement a few phpt, fix some autoload bugs

- Make our autoload handler polite, ensuring that any __autoload() 
functions get added
- Modify phpt calling code so that each phpt files gets its own 
test-case (this lets us run one phpt file at a time)
- Implement phpt for loading, which test varying loading methods of HTML 
Purifier
- Add --disable-phpt and --only-phpt flags
- More descriptive veto messages, also fix test count



git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1552 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier.autoload.php

@@ -2,6 +2,10 @@
 
 if (function_exists('spl_autoload_register')) {
   spl_autoload_register(array('HTMLPurifier_Bootstrap', 'autoload'));
+  if (function_exists('__autoload')) {
+    // be polite and ensure that userland autoload gets retained
+    spl_autoload_register('__autoload');
+  }
 } elseif (!function_exists('__autoload')) {
   function __autoload($class) {return HTMLPurifier_Bootstrap::autoload($class);}
 }