-- CRM-12914 made email addresses clickable in profile search results

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* CRM-12914: Make email addresses clickable in search results
  http://issues.civicrm.org/jira/browse/CRM-12914

1. Added 'field_name' property in the columnheader and used CRM_Core_BAO_UFField::isValidFieldName function to check if its value matches civicrm_uf_field.field_name. Used 'sort_name' as 'field_name' for sort_name as it is a concatenated combination of first name and last name.
2. Removed the key 'sort_name' from $row[] in https://github.com/ravishnair/civicrm-core/compare/CiviHR#L0L586 to match the index values of the columnheaders with that of rows. Also, I checked and found that this key value was not being used anywhere and also this change won't affect any other searches.
3. Used the index value of $rows to identify its matching columnHeader and assigned its value of field_name property to the class attribute.