Merge pull request #526 from yashodha/CRM-12410

CRM-12410
CRM-12274

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* CRM-12274: Merge activity tables into one unified table activity contact table
  http://issues.civicrm.org/jira/browse/CRM-12274
Merge pull request #530 from dlobo/CRM-12274

CRM-12274
more activity clean up
more cleanup