Added callback attribute on thread.py __init__. Using this you call e…

…xternal processes inside the payload

Normally this addon will not brake existing code

src/sgzenity/thread.py

@@ -5,9 +5,10 @@
 
 class WorkerThread(threading.Thread):
 
-    def __init__(self, data=None):
+    def __init__(self, data=None, callback=None):
         threading.Thread.__init__(self)
         self.data = data
+        self.callback = callback
         self.stop = False
 
     def run(self):