Direction fixes
- Updated the config setting attack_direction_change from 15 to 0 (official value); that means that a unit's direction will no longer change when it attacks; knock-back effects from e.g. Firewall will depend on the last direction the target walked into instead (bugreport:1322)
- Ensured that the default direction of a monster is always "north", so that immobile monsters will now always be knocked back to the south by e.g. Firewall on default settings, unless a skill like e.g. Backstab changes their direction (bugreport:1322)