Kill path finding jobs upon interruption, for #1873.

common/buildcraft/core/robots/AIRobotMoveToBlock.java

@@ -95,4 +95,11 @@ public class AIRobotMoveToBlock extends AIRobotMove {
 			prevDistance = Double.MAX_VALUE;
 		}
 	}
+
+	@Override
+	public void end() {
+		if (pathSearchJob != null) {
+			pathSearchJob.terminate();
+		}
+	}
 }

common/buildcraft/core/robots/boards/AIRobotGoToRandomDirt.java

@@ -74,4 +74,10 @@ public class AIRobotGoToRandomDirt extends AIRobot {
 		}
 	}
 
+	@Override
+	public void end() {
+		if (pathFindingJob != null) {
+			pathFindingJob.terminate();
+		}
+	}
 }

common/buildcraft/core/robots/boards/AIRobotSearchBlock.java

@@ -55,4 +55,11 @@ public class AIRobotSearchBlock extends AIRobot {
 			terminate();
 		}
 	}
+
+	@Override
+	public void end() {
+		if (blockScannerJob != null) {
+			blockScannerJob.terminate();
+		}
+	}
 }

common/buildcraft/core/utils/PathFindingJob.java

@@ -12,6 +12,8 @@ public class PathFindingJob extends Thread {
 
 	private PathFinding pathFinding;
 
+	private boolean stop = false;
+
 	public PathFindingJob(PathFinding iPathFinding) {
 		super("Path Finding");
 		pathFinding = iPathFinding;
@@ -19,9 +21,17 @@ public class PathFindingJob extends Thread {
 
 	@Override
 	public void run() {
-		while (!pathFinding.isDone()) {
+		while (!isTerminated() && !pathFinding.isDone()) {
 			pathFinding.iterate();
 		}
 	}
 
+	public synchronized void terminate() {
+		stop = true;
+	}
+
+	public synchronized boolean isTerminated() {
+		return stop;
+	}
+
 }