Report the save-path in a dialog after extracting the device info.
Cleanup: Move nested functions to top of the enclosing function (part 1/2).

To keep changes small, indention levels are not corrected in this change.
Cleanup: Move nested functions to top of the enclosing function (part 2/2).

This change is only fixing the indention levels. Nothing else changed.
Use more spelling parameter name.
Remove unused parameter.
Cleanup: Evaluate pathname of download path only once.

It is now returned by the call to device_extract().
Minimalistic cleanup: Remove extraction dir just after .tgz is created.
Cleanup: Rename ugly variable and simplify bollena tests.
Let tarfile collect the files recursively instead of doing it ourselves.
Minor cleanup: Move some lines.
Remove unused resp. useless code.
Destroy extraction dialog instead of only hiding it.
Make print output more meaningful.
Use more spelling parameter name.
Add myself as an author everywhere.
Change author-email to mine.
Line-wrap LICENCE file.