Adjust darwin build configuration to new project structure.

platform-darwin/Source/Mac/main.m

@@ -0,0 +1,12 @@
+//
+//  main.m
+//  MasterPassword
+//
+//  Created by Maarten Billemont on 04/03/12.
+//  Copyright (c) 2012 Lyndir. All rights reserved.
+//
+
+int main(int argc, char *argv[]) {
+
+    return NSApplicationMain( argc, (const char **)argv );
+}