work on app class and start work on iron

source/app.cpp

@@ -0,0 +1,15 @@
+#include <3ds.h>
+
+#include <amethyst/app.hpp>
+#include <amethyst/ctru.hpp>
+
+namespace amy {
+void app::run() {
+  while (aptMainLoop()) {
+    ull c = ctru::getTime();
+    m_delta = static_cast<double>(c) - static_cast<float>(m_last);
+    m_last = c;
+    main();
+  }
+}
+}  // namespace amy