formation using the
  <tt>ModelConfig</tt> class rather than  via the
  <tt>RooWorkspace</tt> or specifying directly the pdf and parameter
  objects in the constructors. 
Setter methods using pdf instances and parameter lists are maintained in the derived classes, like the <tt>ProfileLikelihoodCalculator</tt> or the <tt>HybridCalculator</tt>, but those passing a string for the name of the pdf have been removed.
<br/>
  </li>
<li>  
All the calculator classes do not keep anymore a pointer to the workspace, b