Experimental build

Added a new branch with an experimental build of the game (if you want to play it, switch to the experimental branch in the game properties on Steam).

A new pathfinding system for all units was added to the experimental build, now the pathfinding is processed in a separate thread from the game. Also, the old path system got rid of snapping to the grid, therefore, the game world can now become completely open, but not in the current game mode, but in the future, which I work on a couple of hours a day due to lack of light. We'll talk about the new mode later.
The saves of the game in the experimental build are the same as in the main one, when it becomes dangerous to play on the main saves, I will inform you about it.