Get microphone sketches to work. Fix permission issue

[jonfroehlich]

The microphone-based sketches aren't working with Chrome? Permissions issue?

• https://developers.google.com/web/updates/2017/09/autoplay-policy-changes#webaudio
• Can't get microphone capture to work reliably in Chrome processing/processing-sound#48

[jonfroehlich]

Works fine in a windowed Chrome browser because this pops up:

[jonfroehlich]

Hmm, actually, seems to work inconsistently. Now getting:

p5.sound.min.js:24 The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page. https://goo.gl/7K7WLu