AI: hooked up to the game.
AI: groups have project-independent motion algorithms.
AI: building construction doesn't overlap.

Various building-ai-related bugfixes.

AI momentarily locked on building mode.
AI: don't plan to build on water.
AI: Automatically use and create manufactures when needed.

This happens every time a movement is not achievable.
AI: Keep track of what gets destroyed / created while building.
AI: don't destroy buildings of the type we build.
Give cars / planes to citizens on mountains / taiga.
AI: Don't build manufactures on tiles which require them.

For instance, don't build a factory on a mountain that the builder can't
access.
AI: Prevent destruction of valuable buildings.
Improved some folks' text snippets.