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/proto/table_marshal.go b/vendor/github.com/golang/protobuf/proto/table_marshal.go
index b167944..5cb11fa 100644
--- a/vendor/github.com/golang/protobuf/proto/table_marshal.go
+++ b/vendor/github.com/golang/protobuf/proto/table_marshal.go
@@ -87,6 +87,7 @@
 	sizer     sizer
 	marshaler marshaler
 	isptr     bool // elem is pointer typed, thus interface of this type is a direct interface (extension only)
+	deref     bool // dereference the pointer before operating on it; implies isptr
 }
 
 var (
@@ -320,8 +321,11 @@
 
 	// get oneof implementers
 	var oneofImplementers []interface{}
-	if m, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(oneofMessage); ok {
+	switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
+	case oneofFuncsIface:
 		_, _, _, oneofImplementers = m.XXX_OneofFuncs()
+	case oneofWrappersIface:
+		oneofImplementers = m.XXX_OneofWrappers()
 	}
 
 	n := t.NumField()
@@ -407,13 +411,22 @@
 		panic("tag is not an integer")
 	}
 	wt := wiretype(tags[0])
+	if t.Kind() == reflect.Ptr && t.Elem().Kind() != reflect.Struct {
+		t = t.Elem()
+	}
 	sizer, marshaler := typeMarshaler(t, tags, false, false)
+	var deref bool
+	if t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8 {
+		t = reflect.PtrTo(t)
+		deref = true
+	}
 	e = &marshalElemInfo{
 		wiretag:   uint64(tag)<<3 | wt,
 		tagsize:   SizeVarint(uint64(tag) << 3),
 		sizer:     sizer,
 		marshaler: marshaler,
 		isptr:     t.Kind() == reflect.Ptr,
+		deref:     deref,
 	}
 
 	// update cache
@@ -448,7 +461,7 @@
 
 func (fi *marshalFieldInfo) computeOneofFieldInfo(f *reflect.StructField, oneofImplementers []interface{}) {
 	fi.field = toField(f)
-	fi.wiretag = 1<<31 - 1 // Use a large tag number, make oneofs sorted at the end. This tag will not appear on the wire.
+	fi.wiretag = math.MaxInt32 // Use a large tag number, make oneofs sorted at the end. This tag will not appear on the wire.
 	fi.isPointer = true
 	fi.sizer, fi.marshaler = makeOneOfMarshaler(fi, f)
 	fi.oneofElems = make(map[reflect.Type]*marshalElemInfo)
@@ -476,10 +489,6 @@
 	}
 }
 
-type oneofMessage interface {
-	XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
-}
-
 // wiretype returns the wire encoding of the type.
 func wiretype(encoding string) uint64 {
 	switch encoding {
@@ -2310,8 +2319,8 @@
 			for _, k := range m.MapKeys() {
 				ki := k.Interface()
 				vi := m.MapIndex(k).Interface()
-				kaddr := toAddrPointer(&ki, false)             // pointer to key
-				vaddr := toAddrPointer(&vi, valIsPtr)          // pointer to value
+				kaddr := toAddrPointer(&ki, false, false)      // pointer to key
+				vaddr := toAddrPointer(&vi, valIsPtr, false)   // pointer to value
 				siz := keySizer(kaddr, 1) + valSizer(vaddr, 1) // tag of key = 1 (size=1), tag of val = 2 (size=1)
 				n += siz + SizeVarint(uint64(siz)) + tagsize
 			}
@@ -2329,8 +2338,8 @@
 			for _, k := range keys {
 				ki := k.Interface()
 				vi := m.MapIndex(k).Interface()
-				kaddr := toAddrPointer(&ki, false)    // pointer to key
-				vaddr := toAddrPointer(&vi, valIsPtr) // pointer to value
+				kaddr := toAddrPointer(&ki, false, false)    // pointer to key
+				vaddr := toAddrPointer(&vi, valIsPtr, false) // pointer to value
 				b = appendVarint(b, tag)
 				siz := keySizer(kaddr, 1) + valCachedSizer(vaddr, 1) // tag of key = 1 (size=1), tag of val = 2 (size=1)
 				b = appendVarint(b, uint64(siz))
@@ -2399,7 +2408,7 @@
 		// the last time this function was called.
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		n += ei.sizer(p, ei.tagsize)
 	}
 	mu.Unlock()
@@ -2434,7 +2443,7 @@
 
 			ei := u.getExtElemInfo(e.desc)
 			v := e.value
-			p := toAddrPointer(&v, ei.isptr)
+			p := toAddrPointer(&v, ei.isptr, ei.deref)
 			b, err = ei.marshaler(b, p, ei.wiretag, deterministic)
 			if !nerr.Merge(err) {
 				return b, err
@@ -2465,7 +2474,7 @@
 
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		b, err = ei.marshaler(b, p, ei.wiretag, deterministic)
 		if !nerr.Merge(err) {
 			return b, err
@@ -2510,7 +2519,7 @@
 
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		n += ei.sizer(p, 1) // message, tag = 3 (size=1)
 	}
 	mu.Unlock()
@@ -2553,7 +2562,7 @@
 
 			ei := u.getExtElemInfo(e.desc)
 			v := e.value
-			p := toAddrPointer(&v, ei.isptr)
+			p := toAddrPointer(&v, ei.isptr, ei.deref)
 			b, err = ei.marshaler(b, p, 3<<3|WireBytes, deterministic)
 			if !nerr.Merge(err) {
 				return b, err
@@ -2591,7 +2600,7 @@
 
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		b, err = ei.marshaler(b, p, 3<<3|WireBytes, deterministic)
 		b = append(b, 1<<3|WireEndGroup)
 		if !nerr.Merge(err) {
@@ -2621,7 +2630,7 @@
 
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		n += ei.sizer(p, ei.tagsize)
 	}
 	return n
@@ -2656,7 +2665,7 @@
 
 		ei := u.getExtElemInfo(e.desc)
 		v := e.value
-		p := toAddrPointer(&v, ei.isptr)
+		p := toAddrPointer(&v, ei.isptr, ei.deref)
 		b, err = ei.marshaler(b, p, ei.wiretag, deterministic)
 		if !nerr.Merge(err) {
 			return b, err