Fix #250 (Desugaring) by using constructors instead of context factory methods

[joeberkovitz]

No description provided.

[rtoy]

Indent this.

[rtoy]

If we're adding constructors, can we actually make the constructors take more arguments than just the context? Like

new BiquadFilter(context, "lowpass", <possibly more parameters like cutoff, etc.>)
new AudioBufferSource(context, buffer, <other parameters like looping, loop points, etc.>)

This requires more design work, but since we're adding something completely new, I think it makes sense to do it now (if we decide to do this) rather than later.

[hoch]

@rtoy I agree with the idea, so we should start a discussion thread of it. I would rather want to throw a property bag. context should be mandatory, but you can opt-in parameters that you want in the property bag.

var hpf = new BiquadFilter(context, { 
  type: 'highpass',
  frequency: 2500
});

[joeberkovitz]

I actually began to do this but felt it would begin to open up a large
number of new debates. We can discuss today on the call.

[joeberkovitz]

Note this PR fixes issue #250

[domenic]

I agree with the property bag idea, with mandatory first parameter of audio context and second parameter being a dictionary allowing customization.

[joeberkovitz]

Be sure to account for change to playbackCategory re #651

[joeberkovitz]

This PR needs a bunch of work to incorporate the property bag concept.