Improve readme and add flag to turn debug info ON for libmbed

[facchinm]

No description provided.

[facchinm]

@per1234 if you could give a grammar/quality check it would be great ❤️

[aentinger]

Looks to me like @per1234 already had a field day. I'll wait with my review until his suggestions have been resolved.

One thing I can say already is that if the intention is to provide information on how to create a debuggable build the text would need to be restructured a bit, like having a headline: "How to enable debugging for ArduinoCore-mbed based boards". I felt that although I personally know what to look for it was not that easy for me to extract that information.

[per1234]

All good now from a nitpick standpoint. I don't have time now to evaluate in detail it from a technical standpoint, but I think this is a very nice enhancement over the previous documentation and script.

Thanks Martino!

[aentinger]

That's my take on improving the issue I mentioned above. What do you guys think?

[per1234]

Looks good to me.

[facchinm]

@aentinger thanks for the patch, it was much needed! I pushed another commit to explain how to change the project config file, hope it's clear enough

[manchoz]

LGTM, too