Add Padding method

id3.go

@@ -28,6 +28,7 @@ type Tagger interface {
 	DeleteFrames(string) []Framer
 	AddFrame(Framer)
 	Bytes() []byte
+	Padding() uint
 	Version() string
 }
 

id3v2.go

@@ -109,6 +109,11 @@ func (t Tag) Bytes() []byte {
 	return append(t.Header.Bytes(), data...)
 }
 
+// The amount of padding in the tag
+func (t Tag) Padding() uint {
+	return t.padding
+}
+
 // All frames
 func (t Tag) AllFrames() []Framer {
 	// Most of the time each ID will only have one frame