Info / Discussion about the update and updateAll events

[hrueger]

@Granjow and me are working on the TypeScript PR (#109) and we started wondering what the events would be used for.

As of now, update is thrown in all drivers (like here) and then bubbled in the main index.js file.

The updateAll event, however, is only fired in the main DMX class.

There's probably a reason behind all those events?