Changes in Version 2.7 (January 2017)

  o optimization is now based on the optimx package
  o the default optimizer is now nlminb (from the stats package)
  o fixed problems in the likelihood with ognormal frailties


Changes in Version 2.6.0 (November 2016)

  o new baseline distrubution: log-skew normal


Changes in Version 2.5.10 (September 2015)

  o added Kendall's tau for the lognormal frailty distrubution


Changes in Version 2.5 (October 2012)

  o new frailty distrubution available: lognormal


Changes in Version 2.01 (June 2012)

  o Added function anova.parfm() to compare models


Changes in Version 1.01 (March 2012)

  o Added stratification


Changes in Version 0.66-2 (February 2012)

  o Added example datasets
