extra option for zones [Even distribution]

[Killaim]

a settting for zones to hold items where if set to

[Even distribution]

the colonists will do their best to make sure that each zone with this setting has a even number of items picked in the menu.

so if there is a total of 100 potatoes and you set 4 zones with this spread out over your colony.
the colonist move 25 potatoes to each of them.

thats my idea thanx.