改变写线程退出方式，不再等待一段时间；

Header_Files/ximeaimager.h

@@ -108,11 +108,13 @@ private:
     int m_iFrameSizeInByte;
     int m_iNumber_WriteDisk;
     MemoryPool<DataBuffer> * m_pool;
+    bool isExitWriteData2Disk;
 
     rgbImage * m_rgbImage;
 
 public slots:
     void write2Disk();
+    void exitWriteData2Disk();
 
 signals:
 };