- Fixed up Linked list
  * operator++ should return reference
  * insert should return reference
  * Should be a copy constructor and operator= for iterator and linked list
  * Added iterator '*' dereference
  * Added const iterator and const begin()/end()
  * Added pop_back
  * front()/back() should return Payload not an internal node repr
  * Updated tests
- Added Stack container type
- Mostly complete implementation of binary search tree
  * Added methods for walking the tree
  * Find now returns a tree* object.