Fix a bug in delete

* modules/access/rtsp/rtsp.c: fixed major bug in realrtsp access. Some incoming data would occasionally be dropped.

  with --enable-corba, but it can now be used through the python binding)

   were drawn when resizing the layout)

and stop doing different things with net_OpenUDP()

* modules/codec/realaudio.c: try to detect dropped subpackets so we don't screw-up the subpackets reordering.

+ popup compile fix (bonus !)

 * doc/skins/skins2-howto.xml: Added documentation for this attribute

* modules/gui/wxwidgets: display and resizing of the embedded playlist should behave a lot better now.

* Don't expand nodes by default
* Distinguish notification types from document to view
  ( update of one item, global change, append of one item)
* Handle item-append 
   - Add a command/callback
   - TODO: Only rebuild the tree image if the newly appended item is 
     visible
* Rename m_lastPos to m_firstPos as it represents the first position
* Beginning of a general ensureVisible function (not working yet)

   XML example:
       <PopupMenu id="sample_menu">
           <MenuItem label="Play" action="vlc.play()" />
           <MenuItem label="Pause" action="vlc.pause()" />
           <MenuSeparator />
           <MenuItem label="Show playlist" action="playlist_window.show()" />
           <MenuItem label="Hide playlist" action="playlist_window.hide()" />
           <MenuSeparator />
           <MenuItem label="Quick open file" action="dialogs.fileSimple()" />
       </PopupMenu>

   To call the menu:
       <Button action="sample_menu.show()" ... />

   Known bug: the popup disappears when the user clicks "too fast" on the
   button: the control refreshes itself in an asynchronous way, and the popup
   dislikes it... so click slowly :)

Do not crash on vlm command: 'new somestring vod enabled', when the user forgot --rtsp-host <ipaddress>:<port> on the vlc commandline.

Case matters when using filenames!

Thanks.

(can be disabled with an advanced option)

First steps towards integrating coreaudio and auhal module into one. It does not actually render digital audio yet.