- Added CostCenter field
  - Added CostCenter model and store

  - Improved error message
  - Added remaining columns to GanttTreeStore (material)

  suitable to be parsed by Sencha ExtJS

  - Added permissions to POST on im_hours

  - Moved main audit_impl into intranet-core
  - Replaced im_project_audit by im_audit

  indicating the type of object (task, project, ticket, ...)

  Fixed issue deleting assignations

  Fixed issue saving Gantt Editor task trees with dependencies:
  Now dependencies are saved in a second "pass"

  Now CRUD for timesheet_task dependencies stored
  as part of the Sencha tree store

- Added workflow updates in order to eliminate
  "modify" as the first transition in a WF

  - Fixed creation of im_biz_object_rel relationship objects
  - Changed semantics of list pages: They now also return
    instances of object sub-types. Example: im_project also
    returns im_ticket and im_timesheet_task objects

  - Added a next-object-id.adp data-source in order to allow the
    GanttEditor to assign task_ids to new tasks. This is necessary
    in order to save the parent/child relationship between tasks