Move engine-api client package

This moves the engine-api client package to `/docker/docker/client`.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

container_pause.go

@@ -0,0 +1,10 @@
+package client
+
+import "golang.org/x/net/context"
+
+// ContainerPause pauses the main process of a given container without terminating it.
+func (cli *Client) ContainerPause(ctx context.Context, containerID string) error {
+	resp, err := cli.post(ctx, "/containers/"+containerID+"/pause", nil, nil, nil)
+	ensureReaderClosed(resp)
+	return err
+}