Don't close the audio reader which might be linked from a shallow copy.

moviepy/audio/io/AudioFileClip.py

@@ -87,7 +87,6 @@ def coreader(self):
     def close(self):
         """ Close the internal reader. """
         if self.reader:
-            self.reader.close_proc()
             self.reader = None
 
     def __del__(self):

tests/test_VideoFileClip.py

@@ -41,6 +41,23 @@ def test_ffmpeg_resizing():
                 assert target == observed
         video.close()
 
+
+def test_shallow_copy():
+    """Call a function which uses @outplace
+       and verify that making a shallow copy and deleting it
+       does not corrupt the original clip."""
+    video_file = 'media/big_buck_bunny_0_30.webm'
+    video = VideoFileClip(video_file)
+    video_copy = video.set_start(1)
+    del video_copy
+    # The clip object buffers 200000 frames, around 5 seconds ahead.
+    # When recentering the buffer, if the new buffer is more than 1000000 frames, around 25s
+    # ahead of the end of the current buffer, the reader will reinitialize and fix self.proc
+    # Thus to trigger the bug, you have to look for a frame between ~5 and ~30 seconds away.
+    # These numbers might vary for different reasons and it would be nice to have a test
+    # which was robust to changes in default buffer size, etc.
+    video.audio.make_frame(15)
+
 
 if __name__ == '__main__':
     pytest.main()