- Add optional borsh support
- Add `digits_mut` method to unsigned integers.
- `As` and `CastFrom` traits no longer const, as const trait support removed from latest nightly.
- `cast_signed` method for unsigned integers.
- `cast_unsigned` method for signed integers.
- `midpoint` method for integers.
- `carrying_add` and `borrowing_sub` methods for signed integers.
- strict methods added.
- added `(bnum) ` prefix to error messages that were lacking it.