closed gop support & flags2 as all bits in flags are used

and a few minor things i forgot to commit ...

Originally committed as revision 2718 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -270,6 +270,7 @@ static const __attribute__((unused)) int Motion_Est_QTab[] =
 #define CODEC_FLAG_H263P_SLICE_STRUCT 0x10000000
 #define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
 #define CODEC_FLAG_SVCD_SCAN_OFFSET 0x40000000 ///< will reserve space for SVCD scan offset user data
+#define CODEC_FLAG_CLOSED_GOP     0x80000000
 /* Unsupported options :
  * 		Syntax Arithmetic coding (SAC)
  * 		Reference Picture Selection