lavfi: add fieldorder filter

Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavfilter/allfilters.c

@@ -46,6 +46,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (CROPDETECT,  cropdetect,  vf);
     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);
     REGISTER_FILTER (FADE,        fade,        vf);
+    REGISTER_FILTER (FIELDORDER,  fieldorder,  vf);
     REGISTER_FILTER (FIFO,        fifo,        vf);
     REGISTER_FILTER (FORMAT,      format,      vf);
     REGISTER_FILTER (FREI0R,      frei0r,      vf);