Update to Swift 3

[soffes]

⚠️ The two upload tests are currently failing so I commented them out. We should fix those before merging this.

[rhysforyou]

@soffes looks like you need to remove the TOOLCHAINS environment variable from .travis.yml, otherwise it's trying to build and test against Swift 2.3.

[sethhoward]

If this code is not brought in via a pod (directly added to a project) which flavor of HTTPURLResponse will be used throughout the code base, Foundation or this? I would argue that this class should be prefixed.

[eliperkins]

You can directly reference via the module, that is, either DVR.HTTPURLResponse or Foundation.HTTPURLResponse.

I think having it that way is most explicit and readable.

[armstrongnate]

I fixed the upload tests in https://github.com/soffes/DVR/pull/1.

[codeOfRobin]

@soffes @n8armstrong Any ETA on when this'll be ready for production?

[eliperkins]

@soffes @hyperspacemark @florin-pop @n8armstrong how do y'all feel about getting this PR up to date and merged into master? I feel like people have been using the swift-3 branches/forks for long enough to vet them. It'd be great to get things like @n8armstrong's fixing of the upload tests and everyone else's work into master soon!

[brentleyjones]

Would love to have this merged!