Repair to the audio in the p5.func "easing3_animation" example

[golanlevin]

The synthesized audio aspect of the easing3_animation demo is very compelling and economical. The audio in this demo no longer works because of browser policy changes regarding audio. For example, running the official online demo at IDMNYU in Chrome produces the error:

The AudioContext was not allowed to start. 
It must be resumed (or created) after a user gesture on the page.

A repaired example can be found online here and in this pull request. Changes include:

• Bumping p5.js and p5.sound.js from 0.5.16 to 1.10.0; removing p5.dom.min.js (no longer used)
• Adding getAudioContext().suspend(); in setup()
• Adding the newish userStartAudio(); function in mousePressed().