Changes in Version 1.9-0

  o The vignette "sandwich-OOP" has been revised, extended and
    released as a technical report.
    
  o Several estfun() methods and some of the meat functions have
    been enhanced and made more consistent.


Changes in Version 1.1-1

  o estfun() methods now use directly the model.matrix() method
    instead of the terms() and model.frame() methods.


Changes in Version 1.1-0

  o sandwich is made object-oriented, so that various types
    of sandwich estimators can be computed not only for "lm"
    models, but also "glm", "survreg", etc.
    To achieve object orientation this various changes have
    been made: a sandwich() function is provided which needs
    a bread and a meat matrix. For the bread, a generic bread()
    function is provided, for the meat, there are meat(),
    meatHC() and meatHAC(). All rely on the existence of a
    estfun() method.
    
  o vcovHC() and vcovHAC() have been restructured to use
    sandwich() together with meatHC() and meatHAC(), respectively.
    
  o A new vignette "sandwich-OOP" has been added, explaining
    the new object-orientation features.
    
  o Various methods to bread() and estfun() have been added,
    particularly for "survreg" and "coxph".