09/18/2004: 0.3-4
  * fixed compiling error for gcc 3.4.2

05/04/2004: 0.3-2
  * added depends: R (>= 1.9.0) for stats

04/20/2004: 0.3-1
  * added namespace

11/20/2003: 0.2-7
  * fixed a code/document mismatch for plot.som


09/27/2003: 0.2-6
  * changed package name from GeneSOM to som. 
  * fixed a code/document mismatch for the yeast data.


04/18/2002: 0.2-4
  * fixed linear initialization using prcomp (thank to Michael Meyer).
  * In linear initialization, now always give the 1st prciple component to the bigger dimension, and one of xdim and ydim can be 1.

12/19/2001: 0.2-1
  new features:
  * provides a som.train function which can perform som training interactively with user inputed code matrix, learning rate, learning radius, training length, etc. 
  * provides a som.update function to update a `som' object from updated training parameters.
  * provides a som.project to project new data onto the map

  Inplementing:
  * changed the underlying c++ matrix classes from lapack++ to tnt.
  * changed .C interface to .Call.
