Update changelog

Fix macOS build

Version update

Merge pull request ashleymills#240 from jcesarmobile/patch-1

Update .swift-version to 4

Update for Swift 2.3

Update for Swift 3

Update for Swift 3

Update README.md

Merge pull request ashleymills#65 from kaishin/master

Add OS X target

Merge pull request ashleymills#63 from younata/master

Enable for use in application extensions