0.4-2

o helper classes: listOrNULL and functionOrNULL
o new slot initfunc, initialize method and 
  complete rewrite of constructors
o new print and show methods
o general code cleanup and several bugfixes
o documentation improvements


0.4-1

o general code cleanup
o iteration is now a generic function
o ... argument added to get-functions
o argument "last" in out()

0.3-14

o euler method for numerical integration

0.3-11 - 0.3-13

several bugfixes and documentation improvements

0.3-10

o some bug fixes and error checking in the accessor functions

0.3-9

o documentation improvements

0.3-8

o made rk4 a generic. This required to include a copy of the 
  original rk4 from the odesolve package but this cosmetic issue
  will be fixed as soon as possible
o improvements of documentation

0.3-7

o renamed class rndwalkModel to rwalkModel
o code cleanup and error checking
o changed implementation of 'selfrefer' and renamed to 'addtoenv'
o documentation issues
o bugfixes

0.3-6

o version presented at useR-2006
o slot 'equations' renamed to 'main'
o new slot 'equations' holding sub-equations callable in main

0.3.1 ... 0.3.5

o complete rewrite using S4 classes instead of S3 lists
o rename of classes and several functions
o several examples and utility functions removed,
  they will appear again in future versions,  separate
  packages or as downloadable examples on WWW.
o the 0.3 branch is incompatible to 0.2.x versions of simecol
o if you have problems porting old models, 
  please ask me for assistance.
