CRM-13842 - expose all activity types to scheduled reminders entity options.

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* CRM-13842: Expose ALL activity types to Scheduled Reminders Entity select
  http://issues.civicrm.org/jira/browse/CRM-13842
Merge branch 'CRM-13842' of github.com:davecivicrm/civicrm-core into davecivicrm-CRM-13842
remove CRM_Core_PseudoConstant::activityType concatenation