This is a complete rewrite of the OO interface to Statistics::Descriptive.
A full description of the new interface can be found in the POD documentation
inside the module, here are the highlights:

*  None of the underlying methods of calculation have been changed.

*  There are two separate, distinct classes in the module, Sparse and Full.
   Full inherits from Sparse and extends it with storage of the data
   and additional methods that depend on analyzing the data based on
   user input (in general).  It should be easy to inherit from
   either of the classes.

*  Minimum and maximum methods are now calculated as part of the
   Sparse class, resulting in a faster access to that data.

*  The indices to the maxima and minima are also available.

*  Methods were added to manually sort the data and prevent subsequent
   sorting of the data, sort_data and presorted, respectively.  This
   should speed up some of the analysis by not repeatedly sorting the
   data.