Update for Swift 4 and @objc inference

Author: kharrison

KeyCommand/KeyCommand.xcodeproj/project.pbxproj

@@ -197,6 +197,7 @@
 					5334D0761DD3B6250032CB00 = {
 						CreatedOnToolsVersion = 8.1;
 						DevelopmentTeam = LCC2J94N44;
+						LastSwiftMigration = 0900;
 						ProvisioningStyle = Automatic;
 					};
 				};
@@ -450,7 +451,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.useyourloaf.KeyCommand;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -463,7 +465,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.useyourloaf.KeyCommand;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};

KeyCommand/KeyCommand/OptionViewController.swift

@@ -63,8 +63,8 @@ class OptionViewController: UIViewController {
         ]
     }
 
-    func performCommand(sender: UIKeyCommand) {
-        guard let key = InputKey(rawValue: sender.input) else {
+    @objc func performCommand(sender: UIKeyCommand) {
+        guard let key = InputKey(rawValue: sender.input!) else {
             return
         }
         switch key {

KeyCommand/KeyCommand/SegueHandlerType.swift

@@ -45,7 +45,7 @@ extension SegueHandlerType where Self: UIViewController, SegueIdentifier.RawValu
     func segueIdentifierForSegue(segue: UIStoryboardSegue) -> SegueIdentifier {
         guard let identifier = segue.identifier,
             let segueIdentifier = SegueIdentifier(rawValue: identifier) else {
-                fatalError("Unknown Segue Identifier \(segue.identifier)")
+                fatalError("Unknown Segue Identifier \(segue.identifier ?? "Missing")")
         }
         return segueIdentifier
     }