Minor changes

Docker-DCO-1.1-Signed-off-by: Glyn Normington <gnormington@gopivotal.com> (github: glyn)
Remove StreamIn and add CopyIn, CopyOut

This enables directories to be shipped around and user and group ids
to be set.

Docker-DCO-1.1-Signed-off-by: Glyn Normington <gnormington@gopivotal.com> (github: glyn)