Add legend to the analyser display

[mikeller]

Currently, when the analyser display is opened, there is no indication of what data stream was used as input for the analyser. This can be confusing, especially when dealing with screenshots:

vs.

A legend should be added to the analyser display to indicate the data stream that the analysis was based on.

[McGiverGim]

This has been broken recently. The name must appear at the bottom right of the analyser. This only happens at full screen?

[mikeller]

@McGiverGim: You are right, the title is there:

It is just very hard to spot behind the green plot - maybe it should go somewhare else like up top centered where it is less likely to be overlaid?

@hydra: Fyi.

[McGiverGim]

Usually the noise is almost zero there, so it is more visible. Maybe adding a black border to the letters will make them clearer. I will play a little with it when I have some time.