2.1.3: First new CocoaPods release in a while

Includes several recent tags to correspond to new CocoaPods release

• silences xcode 9 documentation warning

• other updates from before my involvement that didn't correspond to bona fide CocoaPods releases

1.0.1: Merge pull request #1 from brianmichel/bmichel/fix-potential-leak

Fixes a potential memory leak