Port for macOS (#311)

* merged moonlight-mac with moonlight-ios

* reverted to the original project.pbxproj

* cleaned up the code, fixed lots of unnecessary code duplications

* multicontroller support (not tested)

* new class that can be used for further modularization of the MainFrameViewController

Moonlight macOS/main.m

@@ -0,0 +1,13 @@
+//
+//  main.m
+//  Moonlight macOS
+//
+//  Created by Felix on 09.03.18.
+//  Copyright © 2018 Felix. All rights reserved.
+//
+
+#import <Cocoa/Cocoa.h>
+
+int main(int argc, const char * argv[]) {
+    return NSApplicationMain(argc, argv);
+}