Swift 5.1 and Xcode 11

Update to Swift Package Manager to make compatible with Swift 5.1.
Added Swift Package Manager capabilities to all platforms.
Updated Swift code to take advantage of Swift 5.1 features.
Swiftlint version update to 0.35.0.

Swift 5 and Xcode 10.3 with SPM

Patch version to ensure that Swift Package Manager builds with the latest tools.
Only required for Mac users building with SPM.
It will not be sent to CocoaPods as it is not required by CocoaPods users.

Swift 5 and xcode 10.3

Update build for Swift language version 5.
Update the version of Xcode used to build the project to 10.3
Update the version of Swiftlint used to 0.34.0
Update to use native types, removing some type aliases for clarity.
Remove some unnecessary string copies for efficiency.

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.

Initial Release for Swift 3.1

Initial release for Swift 3.1

Add Foundation imports to classes which use character sets.

Update to Swift 3.1 build with Xcode 8.3

Update to Swift 3.1 build with Xcode 8.3
Changes to build files and documentation to update Swift and xcode versions.
A small change to the precedence order of one operator.

Parser Combinator with docs and tests.

A basic Parser Combinator with documentation and tests.

A set of combinators.
A set of convenience parsers.
A set of operators.

See release notes for full details.