[3.1.0] Get testing working again for all versions

- Standalone testing setup properly with autoload
- Bootstrap autoloader deals more robustly with classes that don't exist, preventing class_exists($class, true) from barfing.
- Cleanup $_reporter to $reporter

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1727 48356398-32a2-884e-a903-53898d9a118a

tests/common.php

@@ -193,7 +193,7 @@ class FailedTest extends UnitTestCase {
     }
     public function test() {
         $this->fail($this->msg);
-        if ($this->details) $this->_reporter->paintFormattedMessage($this->details);
+        if ($this->details) $this->reporter->paintFormattedMessage($this->details);
     }
 }