Soffes HotKey Versions Save

• Update deployment target to 10.13
• Avoid Catalyst to work better with SwiftUI previews @rismay #25
• Fix unused warning @msanders #22

• Swift 5 support
• Add CustomStringConvertible on types
• Add more init(string:) aliases
• Fix podspec on case-sensitive file systems

• Swift 4.2 support
• Support for pausing a hot key

• Swift 4 support
• Add isPaused to HotKey
• Fix issues related to unregistering hot keys
• Add SPM support
• Add CocoaPods support

Initial release