Pgeng

- Added documentation in the code
- Optimized some move functions in `vfx`
- Added support for the colour black in `circle_lighting` and in `Spark._lighting`
- Fixed formatting in the sparks example
- Updated LICENCE for the year 2023

- Fixed a bug when checking length of `Entity.scale`

An update?!

---
- Added byte support to `write_to_file`
- Added more error checking to `Entity`

Removing things? Yes.

I decided to remove `string_number`, it was a not optimized function that didn't add anything to pgeng.\
If you want to do what `string_number` used to do, use
py
from re import findall
def string_number(string):
return [float(i.replace(',', '.')) for i in findall(r'-?\d+[.,]?\d*', string)]


---
- Added `clamp`
- Removed `string_number`
- Removed `int_mode` from nearest
- Added `__all__` variable from vfx and collision packages
- Changed some error messages a little bit
- "vfx/vfx_core.py" is renamed back to "vfx/core.py"

- Renamed "vfx/core", because `help(pgeng.core)` would show `help(pgeng.vfx.core)`
- Very minor fixes and optimizations

- Added `int_location`, `round_location` and `ceil_location`
- Added `left`, `right`, `top` and `bottom` properties to `Tile`
- `Screen.__init__` now checks the types of passed attributes
- `Screen.vsync` default is now platform dependent
- `Polygon` and `Circle` collide functions now use `int_location`
- Optimized `Animations`
- Documentation and other small fixes