Fixed deprecation warnings and index increment

[vfn]

The if inside the generate methods would test index and then increment it, allowing it to go out of bounds.

[andreacremaschi]

Hey @vfn thank you for the PR
Oh, I see, the index thing was definitely wrong, wonder why it didn't pop out before.
I'll check why Travis is complaining before merging.

[vfn]

@andreacremaschi I forgot to update the travis file to use xcode7.3. The PR has been updated, build and tests are fine, but Travis is now crashing https://travis-ci.org/andreacremaschi/GEOSwift/builds/120500155

It looks like a xctool issue facebookarchive/xctool#666

[andreacremaschi]

On a second check, this is wrong: index should be incremented AFTER accessing the element, not BEFORE, something like this:

    public func generate() -> AnyGenerator<T> {
        var index: Int32 = 0
        return AnyGenerator {
            if index < self.count {
                let item = self[index]
                index = index + 1
                return item
            }
            return nil
        }
    }

[vfn]

facebookarchive/xctool#684

[andreacremaschi]

thanks! 🍻

[vfn]

👍