version 0.20 (Oct.1998):
  first public release and distribution via WWW
  use optim

version 0.22.1 (2001-05-17)

version 0.22.2 (2002-01-05)
  fix error in sn.dev.gh, improved qsn

version 0.30 (2002-06-15)
  main change is the addition of routines for (multiple) skew-t distribution;
  also some other routines, e.g. mle for grouped data

version 0.3x (2003--2005)
  added some new functions (these include msn.affine, sn.mmle, sn.Einfo, 
  sn.mle.grouped), fix various errors, and other improvements 
  (eg. improved pst)
  
version 0.4-0 (2006-04-11)
  several changes and additions are included:
  - many routines allow use of composite parameter 'dp'  
  - multivariate normal and t probabilities are now computed via package 'mnormt'
  - use of NAMESPACE introduced
  - some more routines introduced, eg. st.cumulants.inversion
  - various fixes/improvements in documentation