Minor changes and bugfixes for construction and elevator resizing.

- Prevent bulldozing of lobbies. [Game.cpp]

Bugfixes
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- Resizing elevators now correctly repositions cars. [Elevator.cpp]
- Resizing elevators now removes previously unserviced floors if they are no longer within the elevator shaft range. [Elevator.cpp]
- Construction of stairs/escalators now correctly blocked if they are too close to neighbouring stairs/escalators. [Game.cpp]