Updated BTree

Decided to have the BTreeNodes contain LinkedLists and then have a
parent pointer to a BTreeNode and have the child pointers, if not a
leaf, to be a LinkedList of BTreeNodes. It is starting to get confusing
keeping up with them all. I have a split method that works, but finding
the proper placement for new objects added after the split is proving
problematic. Thinking about scrapping it and following the book's array
algorithms.