VOL-1460 Updated core to use voltha-protos instead of local protos
Moved protos to python directory in order to maintain functionaly of containers built there.
Added capability to do local builds of protos
Added instructions on running dep ensure for getting protos.
Updated github.com/golang/protobuf version to v1.3.1

Change-Id: Ia6ef55f07f0d5dcb5b750d7c37b21b71db85bfc4
diff --git a/python/protos/ponsim.proto b/python/protos/ponsim.proto
new file mode 100644
index 0000000..74eb97e
--- /dev/null
+++ b/python/protos/ponsim.proto
@@ -0,0 +1,67 @@
+syntax = "proto3";
+
+option go_package = "github.com/opencord/voltha-protos/go/voltha";
+
+package voltha;
+
+import "google/protobuf/empty.proto";
+import "openflow_13.proto";
+
+
+message PonSimOnuDeviceInfo {
+    int32 uni_port = 1;
+    string serial_number = 2;
+}
+
+message PonSimDeviceInfo {
+    int32 nni_port = 1;
+    repeated PonSimOnuDeviceInfo onus = 2;
+}
+
+message FlowTable {
+    int32 port = 1;  // Used to address right device
+    repeated openflow_13.ofp_flow_stats flows = 2;
+}
+
+message PonSimFrame {
+    string id = 1;
+    bytes payload = 2;
+    int32 out_port = 3;
+}
+
+message PonSimPacketCounter {
+    string name = 1;
+    int64 value = 2;
+}
+
+message PonSimPortMetrics {
+    string port_name = 1;
+    repeated PonSimPacketCounter packets = 2;
+}
+
+message PonSimMetrics {
+    string device = 1;
+    repeated PonSimPortMetrics metrics = 2;
+}
+
+message PonSimMetricsRequest {
+    int32 port = 1;
+}
+
+service PonSim {
+    rpc SendFrame(PonSimFrame)
+        returns (google.protobuf.Empty) {}
+
+    rpc ReceiveFrames(google.protobuf.Empty)
+        returns (stream PonSimFrame) {}
+
+    rpc GetDeviceInfo(google.protobuf.Empty)
+        returns(PonSimDeviceInfo) {}
+
+    rpc UpdateFlowTable(FlowTable)
+        returns(google.protobuf.Empty) {}
+
+    rpc GetStats(google.protobuf.Empty)
+        returns(PonSimMetrics) {}
+
+}