Added LoaderUtil, which has unload.

Hmm, I'm not able to use unloadAndStop() yet.
Perhaps I need to grab an even newer version of the flex SDK,
so it's commented out for now.


git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@669 ed5b42cb-e716-0410-a449-f6a68f950b19

src/as/com/threerings/flash/MediaContainer.as

@@ -328,16 +328,7 @@ public class MediaContainer extends Sprite
                 removeListeners(loader.contentLoaderInfo);
 
                 // dispose of media
-                try {
-                    loader.close();
-                } catch (ioe :IOError) {
-                    // ignore
-                }
-                try {
-                    loader.unload();
-                } catch (e :Error) {
-                    // ignore
-                }
+                LoaderUtil.unload(loader);
                 dispatchEvent(new Event(Event.UNLOAD));
 
                 removeChild(loader);