update for cocoapod

Updated swift version to 4.0 && Updated SwiftyJson to 4.0

add a changelog

CocoaPods 1.1.0.rc.2 (2016-09-13)

Use the SWIFT_VERSION when linting pods. To lint with Swift 3.0 add a
Swift Version file. echo "3.0" >> .swift-version.

travis.yml

Initial commit