Added Gamestate class

NothinFancy/src/include/Gamestate.h

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace nf {
+	class Gamestate {
+	public:
+		Gamestate();
+
+		virtual void onEnter();
+		virtual void onExit();
+	private:
+		//Resource stuff
+	};
+}