Malfunctioning on 32-bit systems and inconsistent type handling

[kimikage]

Bit sequences should be treated as Unsigned, but this program makes heavy use of Int.
As a result, this package does not work on 32-bit systems.
Also, although it works on 64-bit systems, the type handling is inconsistent.

Is this package still maintained?　In other words, is it worth sending a PR?

[GunnarFarneback]

Yes, it is. If 32-bit can be run in CI it would improve the chances that it keeps working.

[kimikage]

Fixed by #21