New setting before starting a game - increase neutral creature growth by x%

[Iwyrith]

There's an option for the mapmaker to make harder monsters (and lower resources) in the editor (map difficulty), but there's no such thing as making them grow faster. Impossible difficulty changes only AI difficulty and not the surroundings.
For discussion matter I suggest making it two options 15% and 30%.
There is an idea to make it on EXPERT and IMPOSSIBLE difficulty as the difficulty now changes only AI behaviour and not the surroundings.