Pgeng

- Added alpha support to `gray_scale` and `gray_shade`

sigh...

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- Changed `Screen` size variables back to tuple/list

This might break some code using TextButtons :)

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- Added `to_json` and `from_json` functions to `Tile`
- Changed how fonts work for `TextButton`, you now give it a font at initialization, not when rendering, so font_size is removed
- Added `__eq__` function to `Tile`, `Circle` and `Polygon`
- Optimized `create_font`
- `Font.get_size` now removes the unnecessary extra pixel for spacing for the last character
- Added `TypeError` to writing files if the data is not a string
- Fixed `Particle.width`
- Changed `failed_imports` to `_failed_imports`
- Fixed `Entity` documentation

- Fixed `TextButton.size` variable

- Fixed `Font.get_size()` width if there was a new line
- Made `Font.render` offset a pygame.math.Vector2 object

- Fixed `Font.get_size()` height
- Made `Screen` size variables pygame.math.Vector2 objects