0.22  2009-04-12
      Cleaned up some documentation.  Released on CRAN

0.19    2009-03-16
    - Fixed various documentation errors that rejected code from CRAN.

0.17    2009-03-15
    - Eliminate 'set' and 'get' methods in favor of '$', '[' and '[['
      - .get and .set retained as functions 
    - Renamed slot holding environment from 'x' to 'env' 
    - Simplified many of the functions
    - 

