2.23.1:
* Port large portions of the code to GIO
* Add audio/x-speex as a supported mime-type
* Update Vala sample plugin and bindings to use new features
* Movie Player:
  - Add an icon to "Clear playlist"
  - Fix a crash when a command-line argument isn't known in the GTK+
    only build
  - Fix the bug report script
  - Fix crasher when trying to load (unsupported) audio CDs
* YouTube Plugin:
  - Make the plugin faster, by downloading less data
  - Don't crash when the server returns HTTP errors
  - Check for required GStreamer plugins in the YouTube plugin
* GStreamer backend:
  - Fix a possible crash when forcing use of ximagesink (as is the case
    for small videos on trailers.apple.com)
* xine-lib backend:
  - Allow loading remote subtitle files using gvfs' fuse
  - Fix potential crasher when copying MRLs from the engine