Implemented a Binary Search Tree Data Structure which implements the ICollection<T> Interface
The brilliant Enumerator code is copied from Scott Michels http://msdn.microsoft.com/en-US/library/ms379572(v=vs.80).aspx and the original idea is based on code by Grant Richins http://blogs.msdn.com/grantri/archive/2004/04/08/110165.aspx