Issue 12504 - Added a loop to scan the include_path to allow test classes to be loaded from extension folders when running civix test.
CRM-12504 - StandardTestSuiteLoader - Tweak layout

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* CRM-12504: Unit Tests cannot be loaded from extension directories due to a particular path expected in PHPUnit_Runner_StandardTestSuiteLoader.php
  http://issues.civicrm.org/jira/browse/CRM-12504
Merge remote-tracking branch 'upstream/4.3' into 4.3-master-2013-05-13-15-41-59