Original commit message from CVS:
A rather large update:
- a new videosink using plain X windows (xvideosink). It uses capsnego to
set up it's formats.
- gstplay uses the new xvideosink and a gtk_socket. The initial window
size is set to 0x0 so you need to resize it before you see something.
- got rid of the video metadata include file in favour of properties and
caps negotiation
- adjusted most plugins to not use the metadata.