Add touch input support, add fast scrolling support for coverflow display mode, fix use after free bug in banner list mode

arm9/source/gui/input/IKeyInputSource.h

@@ -0,0 +1,11 @@
+#pragma once
+#include "InputKey.h"
+
+/// @brief Interface for a source of key input.
+class IKeyInputSource
+{
+public:
+    virtual ~IKeyInputSource() { }
+
+    virtual InputKey Sample() const = 0;
+};