failing dots for graphic file extensions

[ghost]

This is a really nice remaking of super mario. I think you have probably forgotten the dots before the last two file extension parameters at tools.py line 113 (load_all_gfx()). I also wanted to ask if you could show me some sources to understand the magic of relative imports which you have used, i am having troubles doing relative imports in python. Could you tell me where have you learned about it?

Regards, Amir