* Added Items and ItemsByIndex properties to TOrderedDictionary.
* Re-implemented Keys and Values properties of TOrderedDictionary as enumerable collections and removed ValuesByIndex property.
* Added internal, public TKeyCollection, TKeyEnumerator, TValueCollection and TValueEnumerator classes to TOrderedDictionary.
* Updated TestUOrderedDictionary unit re changes and additions to TOrderedDictionary.
* Removed commented out code and implemented TODOs