Background
==========

- Priority scale: High, Medium and Low

- Complexity scale: C1, C2, C4 and C8.  The complexity scale is exponential,
  with complexity 1 being the lowest complexity.  Complexity is a function
  of both task 'complexity' and task 'scope'.

  The general rule of thumb is that a complexity 1 task should take 1-2 weeks
  for a person very familiar with oFono codebase.  Higher complexity tasks
  require more time and have higher uncertainty.

  Higher complexity tasks should be refined into several lower complexity tasks
  once the task is better understood.


Call Management
===============

- Add support for +CSSU / +CSSI notifications.  These can be used to simulate
  the remote party putting the call on hold, retrieving or creating an mpty
  call.

  Priority: Low
  Complexity: C1
