[nostalgia] Make core::init take FileSystem and return Context, add core::setWindowTitle

src/nostalgia/core/userland/gfx_opengl.cpp

@@ -278,7 +278,7 @@ void draw(Context *ctx) noexcept {
 	renderer::drawBackgrounds(id);
 	//bool showDemo = true;
 	//ImGui::ShowDemoWindow(&showDemo);
-	for (const auto cd : ctx->drawer) {
+	for (const auto cd : ctx->drawers) {
 		cd->draw(ctx);
 	}
 	if constexpr(config::ImGuiEnabled) {