If you castle correctly the toMove attribute of the game object wasnt changed.
This is now fixed.

Due to the official nim documentation the snake_case was now swapped
for camelCase.
Tests for nearly any move were added.
A new procedure can initialize a game with a given 8x8 board with pieces and determines if
they have been moved already.

All moves including en-passant and castling are implemented.
Game now features a proof of concept game.
Some cleanup still needs to be done.

The most important movements and even en passant and castling are implemented.
A cli game is not done for now.
An engine is the goal of the project, but will be focussed at the end of the basic development.