#213 Workers build roads before Improvements

[Phil Hall]

Workers should build Improvements on Resources first (assuming they are in working range of a city). The gain from the Improvement is much more immediately useful that the Bonus itself.

[Phil Hall]

I looked into this a bit and there are all sorts of places where Workers are being forced to build roads, including on pretty much any terrain that costs extra movement. I tried commenting most of it out and found that the AI tended to do more poorly as a result. Not sure why, but this should really all be cleaned up.

AI_improveBonus should include code for building roads if the plot is out of our territory (this would only be used for Forts in this mod) or the Bonus has already been improved and is not connected to the capital.