Introduce daemon parameter to DummyProcess

Introduce daemon parameter to multiprocessing.dummy.DummyProcess in order to match the API of multiprocessing.

Author: moi90

Lib/multiprocessing/dummy/__init__.py

@@ -33,8 +33,8 @@
 
 class DummyProcess(threading.Thread):
 
-    def __init__(self, group=None, target=None, name=None, args=(), kwargs=None):
-        threading.Thread.__init__(self, group, target, name, args, kwargs)
+    def __init__(self, group=None, target=None, name=None, args=(), kwargs=None, daemon=None):
+        threading.Thread.__init__(self, group, target, name, args, kwargs, daemon=daemon)
         self._pid = None
         self._children = weakref.WeakKeyDictionary()
         self._start_called = False