Fixing dumb AI/Pathfinding problems

[GhostBlade]

In my first game I ran straight into classic Dwarf Fortress problems:

- Colonists can wall themselves in when building, and then starve to death. (Apparently potted plants blocking movement are a common cause of insanity and starvation.) I believe DF solved this in the latest version BTW. Colonists should analyse what they're building to always ensure an exit way, and avoid walling each other in. And if somehow they end up walled up, they should just smash their way out... after all they all have hand welders

- I kept prioritizing (great feature btw) rebuilding the food paste dispenser, but they abandoned the task without warning. I finally realized that some debris under the blueprint were forbidden, which prevented them from clearing the site to build the device. Most logical solution would be to always consider any object under a building as ok to clear away... or just remove the forbidden flag when putting a blueprint on top of it.

- This last point is more subjective, but I get annoyed when I see that a colonist is very unhappy at seeing an enemy body on the ground, but nobody hauls it to the grave because it's a fairly low priority job. Might be a good occasion for the colonist temporarily disobeying the priorities, and either immediately burying the body or asking somebody (i.e. temporarily changing someone else's priorities) to do it, to stop it from freaking them out.