Re-export num-integer traits

[tcharding]

For users of this library to use div_rem they must add the num-integer dependency to their project. It would be more ergonomic if num-bigint re-exported this trait so users could use use num_bigint::{BigInt, Integer}; instead.

[jvdsn]

I have the same issue, but with the num-traits crate. Are we supposed to manually add num-traits as a dependency to our crate?

[cuviper]

I think the better solution for those that don't actually care about the traits is to add corresponding inherent methods, even though that's more tedious to implement methods in two places.

[jvdsn]

I think the better solution for those that don't actually care about the traits is to add corresponding inherent methods, even though that's more tedious to implement methods in two places.

I personally want to use methods like is_zero or is_one on big integers. I don't really care where the method is implemented, and I don't really care about useing stuff. However, I don't like that I have to explicitly add the num-traits crate as a dependency because I don't use it for anything else. So now I have to make sure the num-traits version stays compatible with the num-bigint version.

For what it's worth, I'm quite new to Rust and I was very surprised I had to explicitly add an extra dependency just for basic methods like is_zero or is_one to work. I did not expect this from the number one "bignum" Rust crate, but maybe I'm missing something.