#53 Wormhole knowledge

[Allan Noordvyk]

Under the current implementation, players know about
all wormholes in existence right from the start of the
game. Instead, wormholes should be more like planets
and only be discovered when the player explores a star
system which is one of the wormhole end-points.

To accomplish this, we will have to create wormhole
knowledge support similar to that used for other
objects in the game.