Shibboleth update (beta), aggregation and rss feed fix

  - Shibboleth configuration is now read from a configuration file  (ULondon)
      - Includes all fields from old settings
      - Also includes an enabled and debug flag
      - Mapping from server variables to User_Object values
      - Constants to be added to new users
      - Logic for setting ability to submit, based on server variable values
  - Fix for some RSS elements causing RSS to not validate (UF)
  - Fix for adding admin rights for a user on an aggregation as only change not saving (UF)