task definition:
  title -- visible title of the task.
  description -- description of the task.
  hook menu -- function to delegate from hook_menu. Params: &$items, $task
  hook menu alter -- function to delegate from hook_menu_alter. Params: &$items, $task
  hook theme -- function to delegate from hook_theme. Params: &$items, $task

  admin name -- if set an admin menu will appear in the delegator UI
  admin description -- to describe the admin menu
  
  admin access callback -- if set, the callback to use to determine administrative 
    access to this task. Defaults to user_access. Note that this is required even
    if delegator isn't handling administration, since this gets used to on handler
    edit forms.
  admin access arguments -- If set, the arguments to use to determine administrative 
    access to this task. Defaults to array('administer delegator');  

  type -- The type of the task, used to determine which handlers can service it.

  subtasks -- can be TRUE in which case it supports subtasks with the default
    configuration or a string (array?) with callbacks to fetch subtask data.
  subtask callback -- A callback which returns just one subtask. Param: $task, $subtask_id
  subtasks callback -- A callback which returns an array of all subtasks. 
    This MUST return an array, even if it's empty.Param: $task

  default handlers -- If the task contains any default handlers, they can be included here.

task names must not contain a - as that is used to separate the task name from the subtask ID.

subtasks implement data very similar to their parent task. In particular, they
implement the following items exactly like their task:
  hook menu
  hook menu alter
  description
  admin name
  admin description
  admin access callback
  admin access arguments