burst: Fixed handling of trailing text; removed -inplace and -quiet.

burst: Fixed handling of trailing text; removed -inplace and -quiet.
The trailing text had been part of the last message extracted, now it is
ignored, conforming to the documentation.
Removing the -inplace switch (thus making -noinplace the default) simplified
the code and removed the possibility to lose data.
-quiet supressed warnings (``message is not in digest format''). Warnings
should be displayed. To though suppress them, redirect stderr to /dev/null.
I was unsure if I should make -verbose the default (i.e. remove -verbose
but have -quiet) as it provides similar useful information like inc(1).
I decided against it, because in Unix silence rules. However, I like to have
``burst: -verbose'' in my profile.