implemented keypad

KeypadSDL.hpp

@@ -0,0 +1,12 @@
+#include "Peripherals.hpp"
+
+#include <SDL2/SDL_events.h>
+#include <array>
+
+class KeypadSDL : public chocochip8::Keypad {
+public:
+  bool isKeyPressed(int key) const override;
+  void processEvent(SDL_Event &e);
+private:
+  std::array<bool, chocochip8::KEY_COUNT> mvKeyDown;
+};