mob_meta.get_node_height:
Moved to pathfinding, and made public (creatura.get_node_height).
Now uses collision box rather than node box, if available, unless flag specifies not to.
Fix for getting node height for nodes with connected node boxes
pathfinding.get_ground_level:
We now have one copy between pathfinding and mob_meta.
Can check a larger range of nodes at different heights.
Takes into account node height of both target node, and the height of the node we're coming from.
pathfinding.get_neighbors:
Get maximum distance mob can travel up/down from mob stepheight.
Improved checking diagonals are clear.
Improved checking vertical clearance, takes into account height of current and target node.
Vertical clearance can cope with nodes that have a different collision and node boxes, like snow.
Vertical clearance has a tiny height adjustment so a 2 node heigh entity can fit through a 2 node gap.
Fixed bug where it was assumed a node was reachable if it's the end goal.
methods.movement_theta_pathfind and movement_pathfind:
Fixed bug that raised goal pos by 0.5 nodes.
1. Spawning radius fixed, we now have a cubic max radius mobs will spawn within, and a spherical min radius mobs won't spawn within.
2. Node light check fixed - we need to check the node above the spawn node, otherwise it always returns zero.
