Created AbstractFeature.
Moved line calculations to OnThirdOrFourthLine.
Removed a TODO.
Merge branch 'NearAnotherStone' into orego8

Conflicts:
	src/edu/lclark/orego/feature/NearAnotherStone.java
BitBoard no longer needs a second array.
Made BitBoardTest clearer with diagrams.
Created BoardObserver and HistoryObserver.
NOT COMPILING. Working on getting Board to notify observers.
HistoryObserverTest now passes.
Created StoneCounter.
finished the NearAnotherStone feature.