Fix callback bug when authing via a token

SlackKit/Sources/Response.swift

@@ -37,7 +37,7 @@ public struct Response {
         var json = [String : AnyObject]()
         json["text"] = text
         json["response_type"] = responseType?.rawValue
-        json["attachments"] = attachments?.flatMap({$0.dictionary()})
+        json["attachments"] = attachments?.map({$0.dictionary()})
         return json
     }
     

SlackKit/Sources/SlackKit.swift

@@ -35,7 +35,9 @@ public final class SlackKit: OAuthDelegate {
     public init(withAPIToken token: String, clientOptions: ClientOptions = ClientOptions()) {
         self.clientOptions = clientOptions
         let client = Client(apiToken: token)
-        self.onClientInitalization?(client)
+        DispatchQueue.main.async(execute: {
+            self.onClientInitalization?(client)
+        })
         clients[token] = client
         client.connect(options: self.clientOptions)
     }