GIFs longer than framePreloadCount do not complete after Swift 2.2 syntax update

[flyinghyrax]

Here is a demo project which exhibits the problem:
https://github.com/mr-seiler/gifu-bug-demo/releases/tag/broken-precache

While working on our fork we've noticed that Gifu would not play through the entirety of a GIF with more frames than the framePreloadCount property of AnimatableImageView.

I used git bisect on a local copy of the repository paired with the demo project linked above and I believe the problem was introduced in the latest commit to master, which contains the updates for the new Swift 2.2 syntax/deprecations. I imagine the problem to be the changes to the Animator class but have not yet confirmed that.