Change chunk sample number to BigEndian

chunks/chunk.go

@@ -45,7 +45,7 @@ func FromData(e Encoding, d []byte) (Chunk, error) {
 	case EncXOR:
 		return &XORChunk{
 			b:   &bstream{count: 8},
-			num: binary.LittleEndian.Uint16(d),
+			num: binary.BigEndian.Uint16(d),
 		}, nil
 	}
 	return nil, fmt.Errorf("unknown chunk encoding: %d", e)

chunks/xor.go

@@ -34,7 +34,7 @@ func (c *XORChunk) Bytes() []byte {
 	b := c.b.bytes()
 	// Lazily populate length bytes – probably not necessary to have the
 	// cache value in struct.
-	binary.LittleEndian.PutUint16(b[:2], c.num)
+	binary.BigEndian.PutUint16(b[:2], c.num)
 	return b
 }