Use main.cpp and disable healing for now.

main.cpp

@@ -0,0 +1,22 @@
+#include "builder.hpp"
+#include "gui.hpp"
+#include <fmt/core.h>
+
+int main()
+{
+  GameEngine game{100};
+  auto backend = SFMLBackend(game);
+  GUI gui(backend);
+  auto builder = Builder(gui, game);
+
+  backend.startup();
+
+  while(backend.is_open()) {
+    builder.event(BuildEvent::GO);
+    gui.main_loop();
+  }
+
+  builder.event(BuildEvent::QUIT);
+  backend.shutdown();
+  return 1;
+}