Bump version to 0.5.1

Merge pull request ole#12 from ole/swift3.2

Swift 3.2 and 4.0 compatibility

Change test

Merge pull request ole#5 from ole/xcodeproj

Make Xcode project with macOS, iOS, tvOS, watchOS targets

Merge pull request ole#4 from ole/travis-ci

Continuous integration setup with Travis CI

Initial public release