add a _listeners property when constructing a MovieClipLoader
add a _listeners property when constructing a MovieClipLoader

and add the loader to the listeners.

mltframework/swfdec,freedesktop-unofficial-mirror/swfdec__swfdec,freedesktop-unofficial-mirror/swfdec__swfdec,freedesktop-unofficial-mirror/swfdec__swfdec,mltframework/swfdec