CRM-12750 - Smarty - Restore patches from CRM-5890

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* CRM-12750: upgrade smarty to 2.6.27
  http://issues.civicrm.org/jira/browse/CRM-12750
* CRM-5890: Validate smarty compile path.
  http://issues.civicrm.org/jira/browse/CRM-5890
CRM-12750 - Add Smarty.class.php to _ORIGINAL_

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* CRM-12750: upgrade smarty to 2.6.27
  http://issues.civicrm.org/jira/browse/CRM-12750
Merge pull request #21 from totten/4.3-smarty-crm-5890

CRM-12750 - Smarty - Restore patches from CRM-5890