Packages which are not freely modifiable and redistributable 
with modifications, or which depend on code which is not 
free.  This includes functions which only permit non-commercial 
use and functions which must be kept together as a package.  
Functions in all other directories must be freely redistributable 
with modifications.  Functions in non-free must be freely 
redistributable for non-commercial use.  Functions of unknown
license should not be included anywhere, since no license implies
default license implies no rights to redistribute.