Factor out screen settings to ScreenSettings struct

It's a bit annoying to pass each screen setting individually, would be
nice if we could just wrap it up in a nice struct and pass that instead.

desktop_version/src/ScreenSettings.h

@@ -0,0 +1,17 @@
+#ifndef SCREENSETTINGS_H
+#define SCREENSETTINGS_H
+
+struct ScreenSettings
+{
+	ScreenSettings();
+
+	int windowWidth;
+	int windowHeight;
+	bool fullscreen;
+	bool useVsync;
+	int stretch;
+	bool linearFilter;
+	bool badSignal;
+};
+
+#endif /* SCREENSETTINGS_H */