Cocoa: Shutdown when window is closed

The application is not very useful once the guest window is closed.
QEMU is not a document-based application; terminating it automatically
saves the user another action and resembles SDL behavior.

v2:
- Use delegate method, suggested by Juha Riihimäki.
Signed-off-by: NAndreas Färber <andreas.faerber@web.de>
Cc: Juha Riihimäki <juha.riihimaki@nokia.com>
Signed-off-by: Nmalc <av1474@comtv.ru>

cocoa.m

@@ -783,6 +783,11 @@ static int cocoa_keycode_to_qemu(int keycode)
     exit(0);
 }
 
+- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication
+{
+    return YES;
+}
+
 - (void)startEmulationWithArgc:(int)argc argv:(char**)argv
 {
     COCOA_DEBUG("QemuCocoaAppController: startEmulationWithArgc\n");