Connecting Signals to other inputs does not always work appropriately

[This demo](https://editor.p5js.org/thomasjohnmartinez/sketches/9bsyBm86Q) passes an oscillator as the param to `osc.amp`, the idea being it acts as a low-frequency oscillator to modulate amplitude. It works correctly.

Passing the LFO to `osc.freq` instead (`osc.freq(lfo)` in the setup method) - which the documentation says is possible, _Or, pass in an object such as an oscillator to modulate the frequency with an audio signal._ - leads to this error:

```
RangeError: Value must be within [0, 3.4028234663852886e+38], got: NaN
```

which is related to `rampTo`.

Of course, that's possibly trying to set an osccilator to a range between 1 and -1 - fairly standard - so I thought I'd use `Oscillator.add` and...

`osc.add is not a function`. Neither is `getFreq`, for that matter. I'm lost; I have p5 2.0.1, sound 0.2.0, and the [listed examples](https://editor.p5js.org/thomasjohnmartinez/collections/Dp0zGclVL) work correctly... but it's unclear at the minute if the error is in code, documentation, or both.