Make target switch wait free

[Dyddye]

When a player holds the target switch key in battle, the battle pauses and the executing player has time to change the target. Meanwhile the other players can't do anything. It would be a nice feature, when they also could change targets using their own switch target key.

• handle inputs of the other players, while one of the player holds target switch key
• make unique battle pause on overlapping switch target keys (i.e. P1 holds key -> pause, P2 holds key, P1 releases key, P2 releases key -> unpause)