[Shtoom] echoaudio patch

[Stefan Alfredsson]

Hello,

When using the 'echo' audio driver, shtoom exists with an exception:

----------------------------------------------------
...
          File "/tmp/sl/shtoom/shtoom/app/phone.py", line 76, in play_wav_file
            self._audio.playWaveFile(fullfname)

          File "/tmp/sl/shtoom/shtoom/audio/converters.py", line 328, in playWaveFile
            if not self._d.isOpen():
        exceptions.AttributeError: EchoAudioDevice instance has no attribute 'isOpen'
----------------------------------------------------

The following patch makes EchoAudioDevice inherit AudioDevice, just as
the other drivers, and therefore also the isOpen().


$ svn diff echoaudio.py
Index: echoaudio.py
===================================================================
--- echoaudio.py        (revision 1651)
+++ echoaudio.py        (working copy)
@@ -2,11 +2,12 @@
 
 # A special audio device. It merely echoes back what you send it.
 
+import baseaudio
 from converters import MediaLayer
 
 opened = None
 
-class EchoAudioDevice:
+class EchoAudioDevice(baseaudio.AudioDevice):
 
     def __init__(self):
         self._data = ''