friendlify some error messages

aqt/errors.py

@@ -50,6 +50,8 @@ class ErrorHandler(QObject):
             return
         if "Pyaudio not" in error:
             return showWarning(_("Please install PyAudio"))
+        if "no default output" in error:
+            return showWarning(_("Please connect a microphone."))
         stdText = _("""\
 An error occurred. It may have been caused by a harmless bug, <br>
 or your deck may have a problem.

aqt/importing.py

@@ -148,7 +148,10 @@ you can enter it here. Use \\t to represent tab."""),
             self.importer.run()
         except Exception, e:
             msg = _("Import failed.\n")
-            msg += unicode(traceback.format_exc(), "ascii", "replace")
+            if "1-character string" in unicode(e):
+                msg += unicode(e)
+            else:
+                msg += unicode(traceback.format_exc(), "ascii", "replace")
             showText(msg)
             return
         finally: