Replay navdata conflict

[wiseman]

If you use the replay plugin and you're also connected to a real drone, you'll end up with two conflicting sources of navdata events running in parallel:

https://github.com/eschnou/ardrone-webflight/blob/776f845919af2f424fd8bcca3c184715819efc0c/plugins/replay/index.js#L45

https://github.com/eschnou/ardrone-webflight/blob/8f81e55967a8797847cf61e18801603ee1a3146b/app.js#L110

The observed effect of this is the HUD and any other user interface (or autonomous navigation) based on navdata will jump between two vehicle states.

[eschnou]

Indeed, in my current use case I only use replay when not connected to a drone, for testing purposes. Do you have a use case where you'd like to use replay combined to a real drone? Which data would you like to see preserved then?

[wiseman]

I don't have a use case for it, other than that having to disconnect from the drone before using replay is another step.

[eschnou]

Ok, if we can safely ignore the 'real' client when in replay mode, then forcing a pause() or end() on the client should do the trick. I'll have a look at it.