Support SIGTERM to stop server gracefully.

Fixes #9.

Author: pekkaklarck

atest/tests/stopping.robot

@@ -13,6 +13,9 @@ SIGINT
 SIGHUP
     Send Signal To Process    SIGHUP
 
+SIGTERM
+    Send Signal To Process    SIGTERM
+
 *** Keywords ***
 Start Server
     Start And Import Remote Library    basics.py   ${TEST NAME}

src/robotremoteserver.py

@@ -63,10 +63,9 @@ def stop_with_signal(signum, frame):
             self._allow_stop = True
             self.stop_remote_server()
             raise KeyboardInterrupt
-        if hasattr(signal, 'SIGHUP'):
-            signal.signal(signal.SIGHUP, stop_with_signal)
-        if hasattr(signal, 'SIGINT'):
-            signal.signal(signal.SIGINT, stop_with_signal)
+        for name in 'SIGINT', 'SIGTERM', 'SIGHUP':
+            if hasattr(signal, name):
+                signal.signal(getattr(signal, name), stop_with_signal)
 
     def _announce_start(self, port_file=None):
         host, port = self.server_address