CRM-15613 - Fix access to undefined property error
CRM-11302 - Enhance unsubscribe form to reduce likelihood of accidental unsubscribes

https://issues.civicrm.org/jira/browse/CRM-11302
CRM-15646 - api.setvalue: Add support for custom fields
Merge pull request #4613 from atif-shaikh/CRM-11302

CRM-11302 - added code which conditionally lists the group(s) that the person is unsubscribing from
Merge pull request #4614 from colemanw/CRM-15646

CRM-15646 - api.setvalue: Add support for custom fields
Merge pull request #4610 from colemanw/CRM-15613

CRM-15613 - Fix access to undefined property error
CRM-15645 Petition email confirmation URL incompatible with WordPress
support for old variable
Merge pull request #4619 from jitendrapurohit/CRM-15645

CRM-15645 Petition email confirmation URL incompatible with WordPress