Added priority output for backlog and requirments which must be
elaborated.  Added requirment tag 'Class' which specifies, if a
requirement is ready for implementation or need more requirment
elaboration.  Added requirment tag 'Note'.

Internal changes: Added lot more requirments to rmtoo itself.
Currently most of the features are now 'self containing'.  It is now
possible with the help of rmtoo to coordinate rmtoo's development.