mainly cleaning, details in description

Cleaning and simplification on many places, nicer handeling of all kinds
of situations and bugs.
After evaluating GOAP and HTN, I am going with Behaviour Trees. Right
now all stands and falls on the pathfinding performance (astar blow up)
so any branches evaluation is out of question. Heuristics is a blind
guess without a navigation graph/mesh. Managing useful graph/mesh
(updated, hierarchical, not eating all memory) is nto worth the effort
right now. Future may bring some solution.
So it looks like a good time to start cutting some trees ;)