Defaults and enable features on rust playground

[dns2utf8]

I tested this change with all features enabled and each one independently enabled.
Current state:

• all enabled
• independently
• docs

I use this to test this PR:

extern crate uuid;

use uuid::Uuid;
use uuid::UuidVersion::*;

fn main() {
    let v = vec![ ("Mac", Mac), ("Dce", Dce), ("Md5", Md5), ("Random", Random), ("Sha1", Sha1) ];
    for variant in v {
        let my_uuid = Uuid::new(variant.1);
        println!("{:?} -> {:?}", variant.0, my_uuid);
    }
}

[KodrAus]

Thanks @dns2utf8! Do you have a case where you need a random v3 or v5 uuid? My understanding was that those types are typically used to get a consistent uuid value for some other identifier. The thing here I'm not sure of is defaulting to the NAMESPACE_DNS root, but maybe the default we'd use for random v3 and v5 uuids is a bit arbitrary either way.

[kinggoesgaming]

We don't touch version number until preparing a release

[dns2utf8]

Done

[dns2utf8]

hi @KodrAus
When I read the docs I was under the impression the feature could be useful, so I don't have an immediate usecase apart from the learning effect on how features in rust work.

I stumbled on uuid after playing on the playground and I would like the playground to include all the features.

[Dylan-DPC-zz]

Hi. Thanks for the contribution but I still don't see the need for this. It just feels like we are adding more complexity for no gain.

[dns2utf8]

One pro would be the crate will work as expected on https://play.rust-lang.org/?gist=118112c0ca3014d3683dfd6db7fa99ef&version=stable

[KodrAus]

Ah I see! Yeh there's not a lot you can do without some of the version features enabled. Making uuid more useful on the playground sounds good to me, even without defaulting more uuid versions.

Is the playground feature just a conventional name that play.integer32.com picks up and includes?

[shepmaster]

Is the playground feature just a conventional name that play.integer32.com picks up and includes?

Yep, but both playgrounds have the same content.

changes requested were applied but overall approval still needs to go for

[KodrAus]

My thoughts are that we should go ahead with just the playground feature here, and then talk about values for other Uuid::new types in another PR.

What do you all think?

[kinggoesgaming]

👍 from me

[Dylan-DPC-zz]

Yeah @KodrAus I agree with that

[Dylan-DPC-zz]

@dns2utf8 can you update your branch with master?

[kinggoesgaming]

@dns2utf8 can you merge master into defaults branch and fix the conglicts

[kinggoesgaming]

@dns2utf8 I want this to be available in uuid@0.6.3 can you merge changes from master and fix the conflicting changes?