Don't return both Ipv4Addr and u32

[faern]

I know I said earlier that I didn't have any more changes before a new release. But after some thinking I realized one thing. What is the reason for returning the tuple (Ipv4Addr, u32) from mask, network and broadcast? I can't see a reason when a caller would want both. Plus, the caller can always go from one to the other very simply. Returning both feels a bit redundant.

I suggest the public API always return the Ipv4Addr version only and internal functions who need the integer representation simply use u32::from internally. Cleaner API plus makes it easier to cast the value. Today if you want the representation in a u64 for example you need to do it in two rows, but with the proposed change it would be possible to do it in one:

let n = u32::from(cidr.mask()) as u64

I didn't submit this as a PR directly since I didn't know if there was any special reason it was designed like this or not. Also it would require a major version bump (0.9.0?). However, it's no hurry to get any of this out. As I will continue to use this library I will probably find more stuff to implement in it in the coming days.

[faern]

I could not stop myself from trying it out 😉 If you want to see how it turned out: https://github.com/faern/ipnetwork/blob/one-return-value/src/ipv4.rs

@achanda

[achanda]

Closed by #16