Fixed the minor issue caused by my #288 fix

I needed to make the game know exactly when the "Speed Up" key had been
released so that the award window can make the game speed go back to its
"Speed Up" state when it knows that this state hasn't been cancelled
because its key hasn't been released while the award screen has been
shown.

I've also modified the pause key callback in world.lua so that if a
player pauses the game while holding down the "Speed Up" key, the game
speed will go back to its "Speed Up" state if the player doesn't release
the "Speed Up" key before they unpause their game.

Problem: foreign keyboard support