Implement Scalar::from_bytes_wide

[arthurgreef]

Describe what you want implemented
Scalar::from_bytes_wide.

Describe "Why" this is needed
A clear and concise description of why you need this to be implemented
We would like to use Sonny for circuits in https://github.com/microsoft/Spartan.

Describe alternatives you've considered
curve25519-dalek but that library is not ZK friendly.

Additional context
The source on github also seems to be out of sync with the crate with the same version number published to crates.io. Can we get a new release?

Thanks.