Absence listing report

Absence listing report


T1. Implement the Report template 
  - The table is essentially displaying a list of activities.
  - The "absence type" column is the activity-type column.
  - The results should always be filtered based on ACLs (ie you can only activities for contacts if you permission to see the contact)
  - The only activity-types that can ever be used or shown are the activity types mentioned in civicrm_absence_type.
  
T2. Register the ReportTemplate and ReportInstance classes (*.mgd.php)