 all this
new functionality.

<h4>Uniform interface for creation of (profile likelihoods) and chi-squared from p.d.f.s</h4>

<p>It is now recommended to use the method <tt>RooAbsPdf::createNLL(RooAbsData&,...)</tt> to
create a likelihood from a p.d.f and a dataset rather than constructing a <tt>RooNLLVar</tt>
object directly. This is because part of the likelihood construction functionality such a using
multiple <tt>Range()</tt>s, or the inclusion for constraint terms are only available through
<tt>createNL