* Updates to support Swift 4.2.
* Updating osx_image on Travis config
* Add additional 4.2 updates in example project and specify swift 4.2 in Recaptcha and Recaptcha-Carthage projects.
* Update RxCocoa with latest swift 4.2 fixes.
* Bump RxSwift dependency to match podfile version.
* Update podfile.lock.
* Bump fastlane and cocoapods versions, specify swift_version in the podspec and remove the deprecated .swift-version file.
* Update Podfile.lock.