Swift not compatible with latest Xcode

[GeoJunkie]

When building for iOS target, I get:
Showing Recent Messages :-1: SWIFT_VERSION '2.3' is unsupported, supported versions are: 4.0, 4.2, 5.0. (in target 'Cartography-iOS')

Can this be updated to Swift 4 to allow compatibility with updated Xcode installations?

[jpsim]

Migrated to Swift 5 in #33, but I think newer versions of Deckset may have lost the apple scripting capabilities that this tool used to rely on.