crypto.py: created a pythonmodule named crypto that stores routines for
  encrypting and decrypting the passwords for the hosts
doc/password_manager_concept.rst: renamed the old concept file
  to password_manager_concept.rst
gnome_connection_manager.py: added imports for the new modules
  crypto and host
  added some minor documentary comments
host.py: created a pythonmodule named host.py that contains a class
  for modelling the login credentials for remote hosts