Introducing support to LaunchControl XL

Initial support for Launch Control XL. New example included in /example/LaunchControlXLDemo/ folder.
This release has an updated reference to Processing 4 core libraries. It is very likely to be compatible with Processing 3 as well, but no guarantees are offered.
Pending issues:

• Sysex messages in MacOS seems not to work. This means settings the LED lights on the controller does not work. This is not a new bug, but it was not detected in V1 as @haschdl did not test extensively on a MacOS.
• There are lots of redundant code. See issue #7

A goal for v2.0.0 release is to fix the Syssex issue.

Implementation of the support to Launch Control XL is a contribution by @poetoflight