Updated RNG seed handling, and cleaned up

[pyrohedgehog]

I changed a handful of things. Mainly

• Changed how the random number generator can have a seed passed to it, to follow more modern patterns, and simplicities.
• Broke apart the file into separate files. For legibility's sake.
• Simplified functions where I could. There aren't many changes, but simplifying where I can for maintainability and legibility helps all the same.
• Renaming a typo(?). I believe 'traversible' is supposed to be 'Traversable'. I checked as best I could that it isn't a regional spelling. I believe it is now correct, but this may cause some issues for existing users.

I hope this helps. Please let me know if you have any questions or concerns!