Raw material import stimulation via stockpiles

[cliffski]

I just added a feature for the next build that will help with analyzing this kind of thing:

New feature demonstration: For tracking import flow to a slot

Short video clip showing new ‘import flow analysis’ feature in Production Line. The little arrow buttons change the ‘resource map’ to show (with green lines) where each resource will be imported from, updated once per second. Helps spot long import lines. Coming in 1.81.