Rework link property configuration system.
This can now handle filters which are added to graphs out of order,
including auto-inserted scale filters. As an added bonus, it can
now detect circular filter chains which wouldn't work anyway.
Commited in SoC by Bobby Bingham on 2007-12-24 03:22:10
Originally committed as revision 12107 to svn://svn.ffmpeg.org/ffmpeg/trunk