Change NatlinkEngine.speak() to turn on the mic after speech

This is to make the expected behaviour consistent for each version
of Dragon. For example, Dragon Home 15 will turn the mic off during
text-to-speech output. This will turn it back on afterwards.

dragonfly/engines/backend_natlink/engine.py

@@ -212,6 +212,12 @@ def speak(self, text):
         """ Speak the given *text* using text-to-speech. """
         self.natlink.execScript('TTSPlayString "%s"' % text)
 
+        # Turn on the mic if necessary so the user can start speaking again.
+        # This is to make the expected behaviour consistent for each version
+        # of Dragon.
+        if self.natlink.getMicState() != "on":
+            self.natlink.setMicState("on")
+
     def _get_language(self):
         import win32com.client
         app = win32com.client.Dispatch("Dragon.DgnEngineControl")