Monitor the stack pointer in the game loop

[ChillerDragon]

We do not stack allocate anything. So every game tick the stack pointer should be exactly the same. If not we could throw with an exit message. Instead of running into the segfault. That error could then show if the stack just changed a bit indicating a missing pop or push depending on the direction. If it is too far off probably something else happend. Maybe someone set the stack pointer manually and that was not intentional or with the wrong value.

We could also monitor some values in the .data and .bss section that we do not expect to change. That could act as early alarm system for writing to the wrong memory sections. This should be one method call in the game loop that could be excluded from the release build for extra performance.