buzzer: tone duration float64, no tone during rest

[aykevl]

Can you describe what bugs this fixes?

[breml]

Yes sure. The first commit makes all the note durations float64, such that these constants can be used with Tone(hz, duration float64) (err error), which expects the duration to be a float.

The second commit makes sure, that the note Rest works as intended. This is, Rest is a pause and and during the pause, there is no sound. The only effect of a Rest is to have a defined time of silence. Without the fix, the Rest does not have any effect, because the duration is a function of the tone (hz) and if this is 0, then everything becomes 0 and the function returns more or less imediatly.

[deadprogram]

Thanks for the fix here @breml now merging.