Fixed obscure RRT* bug.
Bug only apparent when cost function can return negative costs, sometimes resulting in an invalid rewire operation that breaks the tree structure.
There was already a check in place for this, but it was insufficient. It only performed the check on the parent node. This fix performs the check on all ancestor nodes.
plannerarena update
add settings tab to planner arena
merge, but undo Caleb's RRT* fix for now