Mqtt anonymous access option added

[uptoratlen]

Hi, I found your project and loved it right from the start.
I bought two of the Ikea devices and one is already modded. But during the weekend I found a strange issue on my mqtt (First I thought it is the sketch, but it turned out differently...of course :-) ).

Let me explain my issue:
If I try to connect from arduino mqtt PubSubClient with a user and password I get
xxxxxxxx: Socket error on client , disconnecting.
But user and pass are definitely correct (checked with mosquitto_pub)
Same issue in case I leave the config empty, I get the same error.(guess "" is not the same as anonymous ). But as soon as I connect as anonymous it works fine. I checked my mqtt config. And other code running (not arduino ) work fine with user and pass.
Maybe I'm on the wrong track and the issue is not user/pass but client, I need to find out why my mosquitto server does not work as expected.

So the issue is caused by my mosquitto setup, but I could solve the topic by alter your code to use anonymous .
And here goes my proposal. Again, I'm not able to solve the issue by now on my server, but as a work around it eases some pain)

Maybe the issue #13 is related to this? Feel free to edit the PR. I changed the code like a monkey with tool, I bet even you see a benefit you will come up with a better solution.

Again thx for the project.
(Btw. I needed to use a LLC for my Wemos D1 to start as 5V did not work - maybe I will provide a image for the readme, you already mentioned this in a line. But that is a different topic)