Bump version to 3.1.0

Merge pull request #28 from dcordero/swift5

Update to Swift 5

Merge pull request #24 from dcordero/swift4.2

Migrate project to Swift 4.2

Bump version to 2.1.0

Bump version to 2.0.1

Bump to 2.0.0

Bump to 1.0.0

bump version to 0.1.4

Bump version to 0.1.3

Bump version to 0.1.2