CRM-13479 : introduced a display column named 'Enabled?' to distinguish between active and in-active relationsip types

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* CRM-13479: Enabled/Disabled column on the "Relationships Types" admin screen
  http://issues.civicrm.org/jira/browse/CRM-13479
Merge pull request #1729 from pratik-joshi/CRM-13479

CRM-13479 : introduced a display column named 'Enabled?' to distinguish between active and in-active relationsip types