Template: Note that ai.foundPassengers() needs to return a record
Add first cut at AI

My strategy is to seek out "high value" passengers, where value is
determined by money divided by total distance required to fetch and then
deliver the passenger.

The algorithm is adaptive and yields the best result found so far under
CPU-limit pressure.

Distance (and pathing) is determined by breadth-first search.

It's ugly as hell. This is my first lua program, and trAInsported is a
hell of a debug environment. There are still tons of bugs. I don't plan
to put more time into this.