Problem: message_t ctor string inconsistency

[gummif]

Solution: Constructor taking generic ranges including string literals includes the null terminated char in
the message. Deprecate function and add overloads for strings.

This fixes the root cause of a problem observed in #396 and discussed here #397

[sigiesec]

Sorry I am lagging behind somewhat. I will try to give this and your other PRs a closer look in the next days. Is there one particularly urgent?

[gummif]

Alright, nothing urgent, just minor fixes.

[sigiesec]

I still have some problems digesting this rather large PR. Unfortunately, the commits are not self-contained, as some of them fix issues from earlier commits. Is it possible to break this up into some self-contained steps, and rewrite the commits accordingly, in a way that would simplify review?

Is all of this really necessary to fix the issue from #396? (Not saying that the changes shouldn't be done, I am just trying to understand if there is one part fixing #396 and more things that are additional improvements)

[gummif]

I am going to split the unrelated changes into other PRs (see e.g. #416) before the rewrite.

[gummif]

This has been simplified a lot and is ready for another review.

[sigiesec]

Thanks, now it was must easier to review this :)