This adds a command line flag to generate a python visualization script from neteq_rtpplay. Bug: webrtc:8614 Change-Id: Ia6f10d7ff0abac6fdbe9302e7f97a8a12a5bb65b Reviewed-on: https://webrtc-review.googlesource.com/29940 Commit-Queue: Ivo Creusen <ivoc@webrtc.org> Reviewed-by: Alessio Bazzica <alessiob@webrtc.org> Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org> Cr-Commit-Position: refs/heads/master@{#21116}