A set of NSObject

Issue #21

The other day I was trying t

• http://mgrebenets.github.io/swift/2015/06/21/equatable-nsobject-with-swift-2
• http://stackoverflow.com/questions/33319959/nsobject-subclass-in-swift-hash-vs-hashvalue-isequal-vs
• https://useyourloaf.com/blog/swift-hashable/