Merge pull request #119 from Flippo24/patch-1

Clean up instances at program end

Author: pedroCabrera

PyFlow/Core/Common.py

@@ -773,6 +773,8 @@ def __init__(self, cls):
         self.allInstances.append(self)
 
     def destroy(self):
+        if ('destroy' in dir(self.instance)):
+            self.instance.destroy()
         del self.instance
         self.instance = None