move thread package out of selector (because it is add by mistake at the beginning)

webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java

@@ -14,7 +14,7 @@ import us.codecraft.webmagic.pipeline.ResultItemsCollectorPipeline;
 import us.codecraft.webmagic.processor.PageProcessor;
 import us.codecraft.webmagic.scheduler.QueueScheduler;
 import us.codecraft.webmagic.scheduler.Scheduler;
-import us.codecraft.webmagic.selector.thread.CountableThreadPool;
+import us.codecraft.webmagic.thread.CountableThreadPool;
 import us.codecraft.webmagic.utils.UrlUtils;
 
 import java.io.Closeable;

webmagic-core/src/main/java/us/codecraft/webmagic/selector/thread/CountableThreadPool.java → webmagic-core/src/main/java/us/codecraft/webmagic/thread/CountableThreadPool.java

-package us.codecraft.webmagic.selector.thread;
+package us.codecraft.webmagic.thread;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;