Decrease false positives on untitled window detection

The detection algorithm is still dumb; it now thinks a window is
untitled (i.e. good for opening new files in) when its title begins with
"[No Name] - VIM".  This means that it now rejects modified buffers
which haven't been saved to a file.

src/MacVim/MMAppController.m

@@ -967,7 +967,7 @@ typedef struct
         // TODO: This is a moronic test...should query the Vim process if there
         // are any open buffers or something like that instead.
         NSString *title = [[[vc windowController] window] title];
-        if ([title hasPrefix:@"[No Name]"]) {
+        if ([title hasPrefix:@"[No Name] - VIM"]) {
             //NSLog(@"found untitled window");
             return vc;
         }