Fixed an edge case and added reporting code
Fixed an edge case and added reporting code

 o Edge case occured when the node with greatest x coordinate
   has no sibling.  In this case, it will be a left child rather
   than the expected left child.
 o Reporting code gives information about the tree:
    - height
    - width at maximum depth
    - size of heap array
    - number of wasted nodes (theoretical and actual)

spratt/PrioritySearchTree,spratt/PrioritySearchTree,spratt/PrioritySearchTree,spratt/PrioritySearchTree