noise.unregister does not release audio device on linux

[faithanalog]

This causes a large number of pulseaudio streams after awhile of turning eye zoom on and off

minimal test case:

def test():
    return

for i in range(10):
    noise.register('pop', test)
    noise.unregister('pop', test)

This will result in 10 additional recording streams in pulseaudio.

When the file that caused the noises to be registered is reloaded, the streams are finally closed. So for example, if mouse.py is reloaded, all the streams generated from toggling eye zoom are cleared (despite the fact that the actual register/unregister call is in eye_zoom_mouse.py!)

[faithanalog]

same root cause as #42