Log Message:
py-serpent: updated to 1.40

1.40
Added "bytes_repr" option to serializer to serialize byte arrays into \ 
their Python bytes repr escaped form.
(also added BytesNode to the parser where it directly deserializes into a byte array)

This can be more convenient than having to deal with base-64 encoded bytes, but \ 
the serialized data is usually about twice as large and it is slower to process.