Add tvOS targets

[neonichu]

This adds a framework target and test target for tvOS.

[neonichu]

If this gets merged, it would be great if there could also be a new point release and an update of the podspec on trunk to add tvOS support 👌

[boredzo]

Is there an advantage to having a separate target, vs adding AppleTV as a supported platform to the existing target?

[victor]

I needed this library for an AppleTV project, all I needed to do was add tvOS as a deployment target to my local copy of the podspec.
I'd appreciate it if the project adopted an official podspec in the repo itself, and with tvOS support if possible, so as to have a simpler Podfile.

[neonichu]

@boredzo probably not, I didn't know that was possible

[neonichu]

I updated the PR so that it adds tvOS support to the existing CocoaTouch targets — much cleaner, thanks for the suggestion 👍

[boredzo]

Thanks for getting this done!

[neonichu]

Thanks for merging! Would be great if you could also push a new release to CocoaPods trunk at some point with the additional platform support.

[iGranDav]

Hi, just want to up this subject to push the tvOS compatible version to CocoaPods trunk please.