pass AVPacket into av_write_frame()

fixes the random dts/pts during encoding
asf preroll fix
no more initial zero frames for b frame encoding
mpeg-es dts during demuxing fixed
.ffm timestamp scale fixed, ffm is still broken though

Originally committed as revision 3168 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffserver.c

@@ -2163,7 +2163,7 @@ static int http_prepare_data(HTTPContext *c)
                             /* XXX: potential leak */
                             return -1;
                         }
-                        if (av_write_frame(ctx, pkt.stream_index, pkt.data, pkt.size)) {
+                        if (av_write_frame(ctx, &pkt)) {
                             c->state = HTTPSTATE_SEND_DATA_TRAILER;
                         }