Enabled SDL_image's support for PNG and TIFF files and improved the

AssetManager with a hashing function, a linked list structure to store
the hashes as well as a reference counter to support multiple users
sharing the same asset.

include/Renderer.h

@@ -6,6 +6,10 @@
 #include "SDL_video.h"
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif // !__cplusplus
+
 typedef struct renderer Renderer;
 
 Renderer *create_renderer();
@@ -17,4 +21,8 @@ void render_texture(const Renderer *renderer, SDL_Texture *texture, float x,
 void swap_buffers(const Renderer *renderer);
 void destroy_renderer(Renderer *renderer);
 
+#ifdef __cplusplus
+}
+#endif // !__cplusplus
+
 #endif // !RENDERER_H