add demo directory

demo/src/main.cpp

@@ -0,0 +1,20 @@
+/*
+# ______       ____   ___
+#   |     \/   ____| |___|
+#   |     |   |   \  |   |
+#-----------------------------------------------------------------------
+# Copyright 2020, tyra - https://github.com/h4570/tyra
+# Licenced under Apache License 2.0
+# Sandro Sobczyński <sandro.sobczynski@gmail.com>
+*/
+
+#include "engine.hpp"
+#include "demo.hpp"
+
+int main() {
+  Tyra::Engine engine;
+  Tyra::Demo game(&engine);
+  engine.run(&game);
+  SleepThread();
+  return 0;
+}