1.fix writeTag(ITag tag) method bug 2.add support to update duration field on flv meta data tag on append mode
1.fix writeTag(ITag tag) method bug
2.add support to update duration field on flv meta data tag on append mode

bigbluebutton/red5-io,solomax/red5-io,marcus-nl/red5-io,zofuthan/red5-io,bigbluebutton/red5-io,maritelle/red5-io,erichpletsch/red5-io