Add multiply and sum methods to Bytes class.

[mrniko]

Hi! Thanks for such cool lib!

Is it possible to implement Bytes.multiply and Bytes.sum methods?

[patrickfav]

Thanks I'll look into it :)

[patrickfav]

So the problem with this feature is that it would just replicate the features of BigInteger so the the benefit of packing it to the lib is fairly small I guess. (you could easily convert to/from BigInteger)

I would be open to add it as a BytesTransformer (or so could you in your project), so if you're interested I'll encourage you to create a PR.

This would add a new inner class BytesTransformer and should probably support inPlace altering and should have signed/usinged mode.