waiting list signup fixes, CRM-14225

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* CRM-14225: Waitlist signup not working for full paid events
  http://issues.civicrm.org/jira/browse/CRM-14225
Merge pull request #2672 from kurund/CRM-14225

waiting list signup fixes, CRM-14225
Merge pull request #1773 from davejenx/CRM-8338-merge-by-household

CRM-8338 implement CRM_Contact_Form_Task::mergeContactIdsByHousehold(), ...
Merge pull request #2673 from kurund/CRM-8338

backport household merge fixes to 4.4, CRM-8338