Converting an ULID string to a 16-byte array and vice-versa #125

Hello,

I would imagine that it is a common use case to store ULIDs as 16-byte BLOBs in relational databases. But I can't see any public methods to convert a 16-byte array to an ULID string and vice-versa.

I think that at the very least, the crockfordEncode() and crockfordDecode() functions should be made public.

Thanks.