Use daemon threads instead of signals.

Daemonized threads exit once the main program has quit,
and the only threads left running are all daemon threads.

Should fix hanging clients while not trampling over anyone
else's signal handlers.

sleekxmpp/xmlstream/xmlstream.py

@@ -16,7 +16,6 @@ import sys
 import threading
 import time
 import types
-import signal
 try:
     import queue
 except ImportError:
@@ -209,24 +208,6 @@ class XMLStream(object):
         self.auto_reconnect = True
         self.is_client = False
 
-        try:
-            if hasattr(signal, 'SIGHUP'):
-                signal.signal(signal.SIGHUP, self._handle_kill)
-            if hasattr(signal, 'SIGTERM'):
-                # Used in Windows
-                signal.signal(signal.SIGTERM, self._handle_kill)
-        except:
-            log.debug("Can not set interrupt signal handlers. " + \
-                          "SleekXMPP is not running from a main thread.")
-
-    def _handle_kill(self, signum, frame):
-        """
-        Capture kill event and disconnect cleanly after first
-        spawning the "killed" event.
-        """
-        self.event("killed", direct=True)
-        self.disconnect()
-
     def new_id(self):
         """
         Generate and return a new stream ID in hexadecimal form.
@@ -705,6 +686,7 @@ class XMLStream(object):
 
         def start_thread(name, target):
             self.__thread[name] = threading.Thread(name=name, target=target)
+            self.__thread[name].daemon = True
             self.__thread[name].start()
 
         for t in range(0, HANDLER_THREADS):