Implemented new e2e Tests and fixed mess

- Fixed the code mess in steps.py/everything.feature
- Implemented following e2e Tests:
- Saving a game of "Player vs Player"
- Saving a game of "Player vs AI"
- Not Saving a game of "Player vs Player"
- Not Saving a game of "Player vs AI"
- Loading a game of "Player vs Player"
- Loading a game of "Player vs AI"
- Reverting last move