Improve planet handling and building selection AI

[tuomount]

While making AI for those whom survive without food, it would make sense to emphasize buildings for example research, if population research requires two pops. Same thing for goes for all production. So it would make AI build more buildings that benefit and use population where it is more useful.

Also noticed that AI might assign pops on task where it does not benefit. This can happen when diving "blinding" free pops by 4 and division is always 1. Now if space race has for example culture production per 2 artist adding one artist does not benefit anything.