Refactor Move into subclasses

[barrybecker4]

There is a comment in the Move class that reads:

This class is due for a refactoring, it does too much. It * should be divided into a MoveNode, a SetupNode and a RootNode which inherit * from an AbstractNode. This will also bring the object model in closer * correspondence with the structure of an SGF file.

There will also be a need to write a GameInfo class and provide a place

• to attach it to the first distinguishing move in a tree of games beginning
• with the move sequence. This will not be necessary until either loading of
• ANY SGF file is supported, or the creation of multi-game trees is supported.