download step now uses the new StreamIn interface

Signed-off-by: Max Brunsfeld <mbrunsfeld@pivotallabs.com>
upload step now uses StreamOut

Signed-off-by: Max Brunsfeld <mbrunsfeld@pivotallabs.com>
use StreamOut for fetch result step

Signed-off-by: Max Brunsfeld <mbrunsfeld@pivotallabs.com>