Add Event system

- Add abstract Event class
- Add EventDispatcher
- Add Mouse, Key and Window Events

CopiumEngine/src/copium/event/WindowResizeEvent.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "copium/event/Event.h"
+
+namespace Copium
+{
+  class WindowResizeEvent : public Event
+  {
+  private:
+    int width;
+    int height;
+  public:
+    WindowResizeEvent(int width, int height);
+
+    int GetWidth() const;
+    int GetHeight() const;
+  };
+}