Feature added: Restrict Hungry Animals to an area (per age and gender)

[dandiez]

A new area restriction added to send hungry animals to a specific area (separated by gender and age).
The "food need" limit can be adjusted such that only hungry enough animals are sent there.

The idea behind is to have a bit more control in certain cases, like for example:

• If animals are waiting to be tamed (and potentially in the future to be milked or sheared) it happens sometimes that the handler is not available, and the animals get stuck in an area where they either starve or need to be provided food (which would come from the winter reserves).
• It allows to have all animals in a central place and only go out to eat some grass and then come back. Currently you can sort of do this with sleeping spots, but during sleep animals cannot be handled and during the day they roam free far away from the barn.
• You can have animals in a particular area (generally), but have an emergency food stash for hard times. The animals would go there if needed.
• You can have wargs hauling food to the freezer, but prevent them from eating the meat there, because as soon as they are a bit hungry they are sent to a special freezer to feed on corpses, etc.

[dandiez]

Without this workaround, if you load an existing save, the GUI goes crazy (I assume because the new array has some sort of bad initialisation data).
I'm sure there is a better way, checking for null correctly, but after trying that I could not get it to work.

[FluffierThanThou]

Hi dandiez!

First of all, thank you for the suggestion and implementation. As it is, I cannot accept this pull request. I've deliberately kept the other restrict options simple - adding a per gender/age box to each of them would overly complicate the tab.

I'ld be willing to accept a simpler toggle for restricting hungry animals. Alternatively, feel free to keep using your own branch - you've done some good work here!