task/us101-ta57 -- ADP insert to accommodate new columns in
delivery_partner, login_access, system_level_access and login_account
tables

nparcel/adp.py
* support for attribute default_passwords
* refactor the sanitise() method to provide a default password and
  translate the login_account.status column value
* refactor the validate() method to check for valid username and
  password values
* update the process() method to insert default values into the
  login_access table

nparcel/adpdaemon.py
* _start() method passes through the adp_default_password attribute to
  the Adp() class initialisation