cc @behrad would you like to have a look?

Please merge this.
EDIT: Skipping tests because they break? Please dont merge this.

@RobQuistNL LOL, thanks! :)
So, would you like to help?

That feature is really not problematic and not MQTT related, but rather a problem in the actual tests.

This also depend on moscajs/ascoltatori#168

I'm working on fixing those tests you've skipped in this commit. This patch I'm working on will update dependencies, integration of standard, issue #541, and some minor tweaks.
It might take a little bit longer before I've patched everything, because I have two busy weeks coming up. Doing a bit every day, though.

@wuhkuh thank you so much. Keep up with the good work!

@mcollina I'm back again, working on the patch. Exams are approaching so things tend to get slower as studying gets a higher priority now.

Anyway, on topic:
As I've read in the MQTT.js notes: 2.x.x drops support for 0.12. I've checked your commit in this PR and you've updated mqtt version despite this incompatibility. Should mosca drop support for 0.12 or should I revert this change?

How realistic is 0.12 usage, by the way? It is EOL since 2016-12-31, so my personal preference is to drop this. I'm not in charge of these choices, though.

This PR drops support for 0.12 as well.