util pygame

[JaskRendix]

The pull request:

• adds type hints throughout, uses f-strings and the correct type hinting for callables
• makes colorkey handling more robust by checking for valid colorkey types and providing more informative error messages. It also improves the logic for deciding when to use RLEACCEL.
• uses a more Pythonic and safer way to find tilesets and layers by name and adds better error checking for tileset types
• optimizes the simplify function
• adds a check to ensure tiles are square before attempting a diagonal flip to avoid errors
• more consistent with the error messages.
• adds unit tests (successfully before and after)