Swift 5.1 and Xcode 11

Swift 5.1 and Xcode 11 updates.
Added all Apple platforms to Swift Package Manager build.
Removed unnecessary return statements.
Swiftlint version update to 0.35.0.
Promoted Swift Package Manager in the README file.

Swift 4 and Xcode 9.0

Update build for Swift language version 4.
Update the version of Xcode used to build the project to 9.0.
Update the version of Swiftlint used to 0.22.0.
Add failure messages to all simple test failures.
Update format of readme and changelog.

Initial Beta

• Initial beta release for Draughts game string parsing.
• Setup the basic project structure with Swiftlint and TravisCI.
• Give the project targets for iOS, Mac, tvOS and watchOS.
• Make the project available to Cocoapods, Carthage and the SPM.