add Launchpad to examples

[montoyamoraga]

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hi @L05, i copied and pasted the following text from a proposal by @singvisha here is the original link: https://github.com/processing/p5.js-website/issues/636 hope you can make it happen

Hi, This is actually not an issue. I just thought of adding a example of Prototype of Launch Pad as examples. It is actually a multi-touch graphical user Interface which will give an actual feeling of LaunchPad Instrument. It works smoothly on touch devices. It uses p5touchgui library and p5.sound library.

SceenShot of example

I would to add the this example

Thank you.