Change default to always recurse through any given directory

[pepa65]

It makes sense to just always send any specified directory with its whole (recursive) content. Who would say dcp <directory> and not want the directory in its whole depth to be transferred?? Then you never need the -r flag, and it works as intuitively would be expected. And if <directory> happens to be empty, you're just receiving an empty directory, as should be expected and probably intended.