Add initial containerd *Client

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

container.go

@@ -0,0 +1,21 @@
+package containerd
+
+import "github.com/containerd/containerd/api/services/containers"
+
+func containerFromProto(client *Client, c containers.Container) *Container {
+	return &Container{
+		client: client,
+		id:     c.ID,
+	}
+}
+
+type Container struct {
+	client *Client
+
+	id string
+}
+
+// ID returns the container's unique id
+func (c *Container) ID() string {
+	return c.id
+}