[0.912] add food building as normal rather than level up choice
so far play and build city, I always choice food like a garden in order to level up city, unless you lucky had river next to city, most case you had land with no river, and no food resoucre, and if you choice any other building than food, you stuck on that level of city. I see this is not good, and forced to pick food path of level up in order to level city, personal I think food building should add as normal and can build, should not part of level up, that way, you can choice any building without forced you to pick food every time to level up.