devel/R-cran-R.methodsS3: new port

Methods that simplify the setup of S3 generic functions and S3 methods.
Major effort has been made in making definition of methods as simple as
possible with a minimum of maintenance for package developers. For
example, generic functions are created automatically, if missing, and
naming conflict are automatically solved, if possible. The method
setMethodS3() is a good start for those who in the future may want to
migrate to S4. This is a cross-platform package implemented in pure R
that generates standard S3 methods.