`impl<'a> From<&'a [u8]> for Bucket` doesn't adhere Rust conventions

[AnthonyMikh]

The following code is problematic:

https://github.com/seiflotfy/rust-cuckoofilter/blob/c7fea791f1c21deda02a263e69f0fec428e10c61/src/bucket.rs#L96-L105

This code can panic for two reasons: 1) fingerprints contains more than BUCKET_SIZE chunks; 2) fingerprints can't be divided evenly into FINGERPRINT_SIZEd chunks (slice_copy forwards to [T]::copy_from_slice which panics if slices have different lengths). However, the documentation for From trait explicitly claims that conversions defined through From::from should be infallible.

The correct solution in this case would be redo this code into TryFrom impl. Of course, this would break backwards compatibility.