Major Screen changes. (If using the screen class, read the description!!)

Changes which are needed when using the screen class:

- Add `void callConstructor() override { }` to your screen's public header.
- Call `Gui::DrawScreen();` to draw the screen.
- Call `Gui::ScreenLogic(u32 hDown, u32 hHeld, touchPosition touch);` to call the Logic.
- Call `Gui::CallConstructor();` to call the used screen's constructor.
- call `Gui::setScreen(std::make_unique<ScreenName>(), <true/ false, depends if you like to transfer the screen to the usedScreen directly.>);` to set the screen.
- Call `Gui::transferScreen();` in case you like to set the tempScreen to the used one.
- Get rid of the `Gui::screenBack();` calls and use `Gui::setScreen(...)` directly for it.

screen.hpp

@@ -30,13 +30,12 @@
 #include <3ds.h>
 #include <memory>
 
-class Screen
-{
+class Screen {
 public:
 	virtual ~Screen() {}
 	virtual void Logic(u32 hDown, u32 hHeld, touchPosition touch) = 0;
 	virtual void Draw() const = 0;
-private:
+	virtual void callConstructor() = 0;
 };
 
 #endif