Add "quitnow" flag -- set if told to exit.

src/szgPartiview.h

@@ -199,6 +199,7 @@ struct Ppszg : public arMasterSlaveFramework {
   float focallen_;
 
   string cmdbuf_;			// master->slave command transfer buf
+  int   quitnow_;
 
 
   Ppszg();