Nest print thread into a try block

printcore.py

@@ -405,6 +405,7 @@ class printcore():
 
     def _print(self, resuming = False):
         self._stop_sender()
+        try:
             if self.startcb:
                 #callback for printing started
                 try: self.startcb(resuming)
@@ -418,6 +419,10 @@ class printcore():
                 #callback for printing done
                 try: self.endcb()
                 except: pass
+        except:
+            print "Print thread died due to the following error:"
+            traceback.print_exc()
+        finally:
             self.print_thread = None
             self._start_sender()