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/vendor/github.com/golang/protobuf/ptypes/empty/empty.pb.go b/vendor/github.com/golang/protobuf/ptypes/empty/empty.pb.go
index a69b403..b4eb03e 100644
--- a/vendor/github.com/golang/protobuf/ptypes/empty/empty.pb.go
+++ b/vendor/github.com/golang/protobuf/ptypes/empty/empty.pb.go
@@ -1,11 +1,13 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // source: google/protobuf/empty.proto
 
-package empty // import "github.com/golang/protobuf/ptypes/empty"
+package empty
 
-import proto "github.com/golang/protobuf/proto"
-import fmt "fmt"
-import math "math"
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
 
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
@@ -16,7 +18,7 @@
 // is compatible with the proto package it is being compiled against.
 // A compilation error at this line likely means your copy of the
 // proto package needs to be updated.
-const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
 
 // A generic empty message that you can re-use to avoid defining duplicated
 // empty messages in your APIs. A typical example is to use it as the request
@@ -37,17 +39,19 @@
 func (m *Empty) String() string { return proto.CompactTextString(m) }
 func (*Empty) ProtoMessage()    {}
 func (*Empty) Descriptor() ([]byte, []int) {
-	return fileDescriptor_empty_39e6d6db0632e5b2, []int{0}
+	return fileDescriptor_900544acb223d5b8, []int{0}
 }
+
 func (*Empty) XXX_WellKnownType() string { return "Empty" }
+
 func (m *Empty) XXX_Unmarshal(b []byte) error {
 	return xxx_messageInfo_Empty.Unmarshal(m, b)
 }
 func (m *Empty) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
 	return xxx_messageInfo_Empty.Marshal(b, m, deterministic)
 }
-func (dst *Empty) XXX_Merge(src proto.Message) {
-	xxx_messageInfo_Empty.Merge(dst, src)
+func (m *Empty) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Empty.Merge(m, src)
 }
 func (m *Empty) XXX_Size() int {
 	return xxx_messageInfo_Empty.Size(m)
@@ -62,9 +66,9 @@
 	proto.RegisterType((*Empty)(nil), "google.protobuf.Empty")
 }
 
-func init() { proto.RegisterFile("google/protobuf/empty.proto", fileDescriptor_empty_39e6d6db0632e5b2) }
+func init() { proto.RegisterFile("google/protobuf/empty.proto", fileDescriptor_900544acb223d5b8) }
 
-var fileDescriptor_empty_39e6d6db0632e5b2 = []byte{
+var fileDescriptor_900544acb223d5b8 = []byte{
 	// 148 bytes of a gzipped FileDescriptorProto
 	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x92, 0x4e, 0xcf, 0xcf, 0x4f,
 	0xcf, 0x49, 0xd5, 0x2f, 0x28, 0xca, 0x2f, 0xc9, 0x4f, 0x2a, 0x4d, 0xd3, 0x4f, 0xcd, 0x2d, 0x28,