Features:
- Basic game in Player vs Player mode
- Game with custom board size from 4 to 26 (passed as an optional command line argument, default is 8)
- Saving current game to or loading from a file (type "save" at any moment in the game instead of a cell name to save current state, then load it from the main menu)
- Main menu is implemented by switching the terminal to a raw mode, which enables selecting options with the arrow keys
