* port to KIM 2.0

* implement ZBL. But how?

   * subclass of PairTersoff (as LAMMPS does)

   * somehow examine the parameter file to see if ZBL is wanted

   * produce the correct class in the init routine

   * then, make a template out of the "destroy", "reinit", and
     "compute" functions; the template parameter is the class
     PairTersoff or PairTersoffZBL

   * make real, static functions that just call the correct template
     and pass those to KIM (again the init routine has to have the
     "if"s to decide which one)

   PROBLEM: how to _optionally_ publish the additional ZBL params?

   PROBLEM 2: now this also needs to be ported to process_dEdr...