#13 Delay for monster spawners

[Tristan de Ines]

I think that monster spawning eggs (I think they are
eggs) should have a delay value which is set to a
certain number and is counted down every game hour or
so. If the player returns to a spawning-egg area, and
that eggs value isn't zero jet, no monsters are
spawned. The number should be high for powerful and
rare monsters and relatively low for common creatures.