Bump to version 4.0 in ancillary files

Add swift version file

Fix regression in update method to fix matthewpalmer#110

Merge pull request matthewpalmer#108 from matthewpalmer/2.0.7

2.0.7

Bump podspec

Bump podspec version

Merge pull request matthewpalmer#93 from gambcl/gambcl-carthage-tvos

Added support for tvOS for Carthage builds

Update README.md

Add links to Apple's docs

Fixes matthewpalmer#78

Update travis