Intermediate refactor to move everything over to using the textures module rather than everyone using one TexturePack thing.

tests/textures.cpp

@@ -0,0 +1,17 @@
+#include <catch2/catch_test_macros.hpp>
+#include <fmt/core.h>
+#include <string>
+#include "textures2.hpp"
+
+using namespace fmt;
+
+TEST_CASE("test texture management", "[textures]") {
+
+  textures::init();
+  auto spider = textures::get("hairy_spider");
+
+  auto image = textures::load_image("assets/hairy_spider-256.png");
+
+  auto img_ptr = textures::get_surface(0);
+  REQUIRE(img_ptr != nullptr);
+}