VOL-1596 Add Support for handling multicast groups in OpenOLT Adapter.
VOL-1595 Add Support for handling multicast flows in OpenOLT Adapter.

Depends voltha-protos from the patch below:
https://gerrit.opencord.org/#/c/16690/

Change-Id: I1cc9900bd6400bb31aed11beda674138838a21d2
diff --git a/vendor/github.com/opencord/voltha-lib-go/v3/pkg/adapters/iAdapter.go b/vendor/github.com/opencord/voltha-lib-go/v3/pkg/adapters/iAdapter.go
new file mode 100644
index 0000000..3b86ac5
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-lib-go/v3/pkg/adapters/iAdapter.go
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package adapters
+
+import (
+	ic "github.com/opencord/voltha-protos/v3/go/inter_container"
+	"github.com/opencord/voltha-protos/v3/go/openflow_13"
+	"github.com/opencord/voltha-protos/v3/go/voltha"
+)
+
+//IAdapter represents the set of APIs a voltha adapter has to support.
+type IAdapter interface {
+	Adapter_descriptor() error
+	Device_types() (*voltha.DeviceTypes, error)
+	Health() (*voltha.HealthStatus, error)
+	Adopt_device(device *voltha.Device) error
+	Reconcile_device(device *voltha.Device) error
+	Abandon_device(device *voltha.Device) error
+	Disable_device(device *voltha.Device) error
+	Reenable_device(device *voltha.Device) error
+	Reboot_device(device *voltha.Device) error
+	Self_test_device(device *voltha.Device) error
+	Delete_device(device *voltha.Device) error
+	Get_device_details(device *voltha.Device) error
+	Update_flows_bulk(device *voltha.Device, flows *voltha.Flows, groups *voltha.FlowGroups, flowMetadata *voltha.FlowMetadata) error
+	Update_flows_incrementally(device *voltha.Device, flows *openflow_13.FlowChanges, groups *openflow_13.FlowGroupChanges, flowMetadata *voltha.FlowMetadata) error
+	Update_pm_config(device *voltha.Device, pm_configs *voltha.PmConfigs) error
+	Receive_packet_out(deviceId string, egress_port_no int, msg *openflow_13.OfpPacketOut) error
+	Suppress_event(filter *voltha.EventFilter) error
+	Unsuppress_event(filter *voltha.EventFilter) error
+	Get_ofp_device_info(device *voltha.Device) (*ic.SwitchCapability, error)
+	Get_ofp_port_info(device *voltha.Device, port_no int64) (*ic.PortCapability, error)
+	Process_inter_adapter_message(msg *ic.InterAdapterMessage) error
+	Download_image(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+	Get_image_download_status(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+	Cancel_image_download(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+	Activate_image_update(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+	Revert_image_update(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+}