Add current gatherers count next to resource count

[Kieran P]

Add the amount of workers in a number next to the current amount of that resource, along with a tooltip.

e.g. If user has 5000 food, and 10 people gathering food (from any source), show

[food_icon] 5000 / 10

And when user hovers over the amounts, both should display a tooltip with:

Food resource: 5000
Number of gatherers: 10

Do the same for all resource types.