Try to avoid server hangs.

It seems that the most common cause (if not the only cause) of the dictation server hangs is natlink.natConnect() hanging. Previously, in an effort to coalesce multiple connections to natlink across a single server session, we always connected to natlink upon connection to the server. This was hanging, and in most cases, we did not even need to use natlink in that server session.

So, instead, connect lazily to natlink.

dictation_server.pyw

@@ -62,20 +62,31 @@ def set_taskbar_autohide(on):
 CLIPBOARD_RTF = win32clipboard.RegisterClipboardFormat('Rich Text Format')
 
 class DragonService(rpyc.Service):
+    __slots__ = ('natlink_connected',)
+
     should_keep_serving = True
 
     def on_connect(self):
-        natlink.natConnect(True)
+        self.natlink_connected = False
 
     def on_disconnect(self):
-        natlink.natDisconnect()
+        if self.natlink_connected:
+            natlink.natDisconnect()
+
+    def natlink(self):
+        if not self.natlink_connected:
+            logging.info('connecting...')
+            natlink.natConnect(True)
+            logging.info('connected')
+            self.natlink_connected = True
+        return natlink
 
     def exposed_get_mic_state(self):
-        return natlink.getMicState()
+        return self.natlink().getMicState()
 
     def exposed_set_mic_state(self, state):
         try:
-            natlink.setMicState(state)
+            self.natlink().setMicState(state)
         except natlink.NatError:
             if state != 'on':
                 raise