Substantial refactoring to implement correct Naive, UCT Monte Carlo tree search methods.

Removed unnecessary distinction between policy and tree search (tree search is a special kind of policy).
Calculation of all valid moves / arbitrary sets of moves is now a seperate class, as it serves a different purpose than a policy.
Introduced regression error in AlphaBeta test.

src/net/woodyfolsom/msproj/policy/RandomMovePolicy.java

@@ -0,0 +1,66 @@
+package net.woodyfolsom.msproj.policy;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import net.woodyfolsom.msproj.GameConfig;
+import net.woodyfolsom.msproj.GameState;
+
+
+public class RandomMovePolicy implements Policy {
+
+	/**
+	 * Does NOT modify the gameState.
+	 */
+	public String getAction(GameConfig gameConfig, GameState gameState,
+			String color) {
+		GameState gameStateCopy = new GameState(gameState);
+		List<String> emptyCoordinates = gameStateCopy.getEmptyCoords();
+
+		while (emptyCoordinates.size() > 0) {
+			String randomMove = emptyCoordinates
+					.get((int) (Math.random() * emptyCoordinates.size()));
+			if (gameStateCopy.playStone(color, randomMove)) {
+				return randomMove;
+			} else {
+				emptyCoordinates.remove(randomMove);
+			}
+		}
+
+		return PASS;
+	}
+
+	/**
+	 * Attempts to generate up to nMoves random moves on behalf of the specified
+	 * player. Will return at least one move, which may be 'pass' if random
+	 * search does not success in discovering a valid move. Does NOT modify the
+	 * gameState.
+	 * 
+	 * @param gameConfig
+	 * @param gameState
+	 * @param color
+	 * 
+	 * @return
+	 */
+	public List<String> genMoves(GameConfig gameConfig, GameState gameState,
+			String color, int nMoves) {
+		GameState gameStateCopy = new GameState(gameState);
+		List<String> emptyCoordinates = gameStateCopy.getEmptyCoords();
+		List<String> randomMoves = new ArrayList<String>();
+
+		while (emptyCoordinates.size() > 0 && randomMoves.size() < nMoves) {
+			String randomMove = emptyCoordinates
+					.get((int) (Math.random() * emptyCoordinates.size()));
+			if (gameStateCopy.playStone(color, randomMove)) {
+				randomMoves.add(randomMove);
+			}
+			emptyCoordinates.remove(randomMove);
+		}
+
+		if (randomMoves.size() == 0) {
+			randomMoves.add(PASS);
+		}
+
+		return randomMoves;
+	}
+}