plugins: std -- Make args area to be the same as in criu

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
plugins: Add shmem stub

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
TODO: logging plugin is done

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>